List pull requests
Example
iex> client = %Github.Client{access_token: "access_token"}
iex> client |> Github.Pulls.list!(repo_path: "WorkflowCI/github", state: "open", per_page: 30, page: 1)
%Github.Client.Response{
body: [%{"number" => 10, ...}],
status: 200,
...
}