[Perl] Support Patch (HTTP method)

[wing328]

HTTP::Request::Common does not support PATCH (HTTP verb) at the moment.

Suggested implementation: using HTTP::Request instead

Line: https://github.com/swagger-api/swagger-codegen/blob/master/modules/swagger-codegen/src/main/resources/perl/ApiClient.mustache#L117

If you have questions or want to work on this, please reply to let the community know.

Ref: https://github.com/swagger-api/swagger-codegen/wiki/Guidelines-for-Contribution