Additionally updating existing *Options to include:
 - UpdatedAfter/Before - "Return merge requests updated on/before/after the given time"
 - SourceBranch- "Return merge requests with the given source branch"
 - TargetBranch - "Return merge requests with the given target branch"
 - Search - "Search merge requests against their title and description"

Corrected some outdated documentation.

More info here: https://docs.gitlab.com/ce/api/merge_requests.html#list-group-merge-requests