ci!: update workflow

[Fdawgs]

BREAKING CHANGE: Drops support for EOL node 12 and 15; adds support for node 18

This PR:

• Drops support for EOL node versions
• Removes Git credentials/SSH keys after checkout as a security precaution by setting persist-credentials: false, they are not used after the initial checkout
• Enables concurrency; see related docs, this allows a subsequently queued workflow run to interrupt previous runs in PRs
• Adds a conditional if to the automerge job; this stops the job from running if the user is not Dependabot, saving a few seconds CI run time

closes #427
closes #431
closes #456

[mcollina]

@Fdawgs apparently this fails on CI on Node v18. Could you take a look?

[Fdawgs]

Not 100% on this one. Seems to be an issue with passing pfx to tls.createSecureContext(). Swapped it out with a generated .pfx file and it throws an error as well:

I've looked through the V17 and V18 changelogs and can't spot any breaking changes in this area. 😢

[mcollina]

Maybe skips?

[Fdawgs]

Maybe skips?

Found the issue: nodejs/node#40672

Have recreated the test pkcs12 file using OpenSSL v3 and it now uses a supported cipher.

[Fdawgs]

Don't know if it's worth adding chalk and pretty-bytes to the list of dependencies to not automerge, considering they're now fully ESM?

[mcollina]

Don't know if it's worth adding chalk and pretty-bytes to the list of dependencies to not automerge, considering they're now fully ESM?

add them!

[Fdawgs]

add them!

Cool beans, all done @mcollina

Edit: CI failure unrelated to this, was fine prior to c69d1e4

[mcollina]

lgtm

[mcollina]

CI is failing :(

[Fdawgs]

CI is failing :(

There we go!

[mcollina]

thx