Allow specifying custom parameters

[lexisother]

The library locks you into providing only specific parameters. For example, \Api\CurrentUser:

The /user/repos endpoint has more parameters than just these, though, such as per_page, which is now being locked to 30 because users cannot specify a custom value.

If there is however a way to specify custom options without having to do any hacky things with $client->getHttpClient, I'd love to hear.

[reedy]

https://github.com/KnpLabs/php-github-api/blob/0e2399c93eb53be2243871c420eb1c6641cf0c7b/doc/result_pager.md can be used as part of a workaround (for example, I wanted to get all issues in a repo)...