bug: query string set incorrectly during retries

[viktor-f3]

We have run into an issue when using this in the PagerDuty Terraform provider we get malformed URLs when a request with a query string is rate limited.

In our specific case it was a call to /members?offset=100 would result in /members?offset=100?offset=100 on the retry, which would cause a 400 to be returned.

Fixed by this PR: #145

[imjaroiswebdev]

Issue solved in #145