Add patch() Method with URL in WireMock HTTP client

[Joel-Schaltenbrand]

In the original code, there was no 'patch' method available in the WireMock class. I added the 'patch' method, which allows creating a mapping from a url-string for HTTP PATCH requests.

(New PR because the old one was closed due to accidental deletion of the fork.)

References

• Already existing code for the other methods (Get, Post, Put etc.)

Submitter checklist

• The PR request is well described and justified, including the body and the references
• The PR title represents the desired changelog entry
• The repository's code style is followed (see the contributing guide)
• Test coverage that demonstrates that the change works as expected
• For new features, there's necessary documentation in this pull request or in a subsequent PR to wiremock.org

[oleg-nenashev]

No need in the test IMHO