regru: update authentication method

[tcaty]

Hi! Recently I've faced an issue with obtaining certificate via dns challenge for domain hosted by provider regru. This provider has updated API, so now authentication via query params is not allowed.
You can check it with simple request from API docs:

curl -X POST "https://api.reg.ru/api/regru2/nop?password=test&username=test"

API will respod with

{
   "charset" : "utf-8",
   "error_code" : "QUERY_PARAMS_DISALLOWED",
   "error_params" : {
      "command_name" : "nop"
   },
   "error_text" : "Query string parameters are disallowed. Pass parameters in form data.",
   "messagestore" : null,
   "result" : "error"
}

But if we send creds in form data like this:

curl -X POST -F "username=test" -F "password=test" "https://api.reg.ru/api/regru2/nop"

API will respond correctly

{
   "answer" : {
      "login" : "test",
      "user_id" : 0
   },
   "charset" : "utf-8",
   "messagestore" : null,
   "result" : "success"
}

So this PR is about changing authentication method from query params to form data.

[ldez]

Can you run the following command and put the output of this command to a comment?

rm -rf .lego

REGRU_USERNAME=xxxxxx \
REGRU_PASSWORD=yyyyyy \
./lego -m your@email.com --dns regru -d *.example.com -d example.com -s https://acme-staging-v02.api.letsencrypt.org/directory run

Note the wildcard domain is important.

[tcaty]

Sure, I'll provide the result after some hours

[tcaty]

It works, I've got certificates

REGRU_USERNAME=xxx \
REGRU_PASSWORD=yyy \
REGRU_PROPAGATION_TIMEOUT=300 \
lego -m my@email.com --dns regru --dns.resolvers ns1.reg.ru -d *.example.com -d example.com run

2024/11/08 09:29:34 No key found for account my@email.com. Generating a P256 key.
2024/11/08 09:29:34 Saved key to /.lego/accounts/acme-v02.api.letsencrypt.org/my@email.com/keys/my@email.com.key
2024/11/08 09:29:34 Please review the TOS at https://letsencrypt.org/documents/LE-SA-v1.4-April-3-2024.pdf
Do you accept the TOS? Y/n
Y
2024/11/08 09:29:36 [INFO] acme: Registering account for my@email.com
!!!! HEADS UP !!!!

Your account credentials have been saved in your Let's Encrypt
configuration directory at "/.lego/accounts".

You should make a secure backup of this folder now. This
configuration directory will also contain certificates and
private keys obtained from Let's Encrypt so making regular
backups of this folder is ideal.
2024/11/08 09:29:36 [INFO] [*.example.com, example.com] acme: Obtaining bundled SAN certificate
2024/11/08 09:29:37 [INFO] [*.example.com] AuthURL: https://acme-v02.api.letsencrypt.org/acme/authz-v3/427223100027
2024/11/08 09:29:37 [INFO] [example.com] AuthURL: https://acme-v02.api.letsencrypt.org/acme/authz-v3/427223100037
2024/11/08 09:29:37 [INFO] [*.example.com] acme: use dns-01 solver
2024/11/08 09:29:37 [INFO] [example.com] acme: Could not find solver for: tls-alpn-01
2024/11/08 09:29:37 [INFO] [example.com] acme: Could not find solver for: http-01
2024/11/08 09:29:37 [INFO] [example.com] acme: use dns-01 solver
2024/11/08 09:29:37 [INFO] [*.example.com] acme: Preparing to solve DNS-01
2024/11/08 09:29:37 [INFO] [example.com] acme: Preparing to solve DNS-01
2024/11/08 09:29:37 [INFO] [*.example.com] acme: Trying to solve DNS-01
2024/11/08 09:29:37 [INFO] [*.example.com] acme: Checking DNS record propagation. [nameservers=ns1.reg.ru:53]
2024/11/08 09:29:39 [INFO] Wait for propagation [timeout: 5m0s, interval: 2s]
2024/11/08 09:29:40 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:29:42 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:29:44 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:29:46 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:29:58 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:00 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:12 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:14 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:16 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:18 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:20 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:22 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:24 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:26 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:28 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:31 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:33 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:35 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:37 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:39 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:41 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:43 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:55 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:57 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:30:59 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:31:01 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:31:03 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:31:15 [INFO] [*.example.com] acme: Waiting for DNS record propagation.
2024/11/08 09:31:32 [INFO] [*.example.com] The server validated our request
2024/11/08 09:31:32 [INFO] [example.com] acme: Trying to solve DNS-01
2024/11/08 09:31:32 [INFO] [example.com] acme: Checking DNS record propagation. [nameservers=ns1.reg.ru:53]
2024/11/08 09:31:34 [INFO] Wait for propagation [timeout: 5m0s, interval: 2s]
2024/11/08 09:31:40 [INFO] [example.com] The server validated our request
2024/11/08 09:31:40 [INFO] [*.example.com] acme: Cleaning DNS-01 challenge
2024/11/08 09:31:40 [INFO] [example.com] acme: Cleaning DNS-01 challenge
2024/11/08 09:31:40 [INFO] [*.example.com, example.com] acme: Validations succeeded; requesting certificates
2024/11/08 09:31:41 [INFO] [*.example.com] Server responded with a certificate.

[ldez]

LGTM