Must fetch entire PR using get-one-PR API

The result is smaller when you fetch all the PRs as a list instead of
fetching them one at a time.  We need some of the fields which are in
the single-PR view but not the list-PR view.

Author: nat-henderson

assets/lib/filters/all.rb

@@ -11,7 +11,7 @@ def initialize(pull_requests: [], input: Input.instance)
 
     def pull_requests
       @pull_requests ||= Octokit.pulls(input.source.repo, pull_options).map do |pr|
-        PullRequest.new(pr: pr)
+        PullRequest.new(pr: Octokit.pull_request(input.source.repo, pr['number'], pull_options))
       end
     end