support passing in params for Deployments.list method

[batmany13]

Looking at GitHub's Deployments api docs, it describes the ability to filter deployments by "sha", "ref", "task" and "environment". There doesn't seem to be the ability to pass in optional query params to the Tentacat.Repositories.Deployments.list call. This will be convenient, for instance, in the case of finding all deployments associated with a PR/sha value.