Add missing fields to streams

[nick-mccoy]

Following fields are missing from the streams:

• Pull Requests
  [ '_links', 'assignee', 'assignees', 'author_association', 'base', 'comments_url', 'commits_url', 'diff_url', 'head', 'html_url', 'issue_url', 'labels', 'locked', 'merge_commit_sha', 'milestone', 'patch_url', 'requested_reviewers', 'requested_teams', 'review_comment_url', 'review_comments_url', 'statuses_url', ]
• Reviews
  ['_links', 'author_association', 'submitted_at', 'user.avatar_url', 'user.events_url', 'user.followers_url', 'user.following_url', 'user.gists_url',
  'user.gravatar_id', 'user.html_url', 'user.organizations_url', 'user.received_events_url', 'user.repos_url', 'user.site_admin', 'user.starred_url', 'user.subscriptions_url', 'user.type', 'user.url']
• Stargazers
  ['user.avatar_url', 'user.events_url', 'user.followers_url', 'user.following_url', 'user.gists_url', 'user.gravatar_id', 'user.html_url', 'user.login', 'user.organizations_url', 'user.received_events_url', 'user.repos_url', 'user.site_admin', 'user.starred_url', 'user.subscriptions_url', 'user.type', 'user.url']
• Collaborators
  ['avatar_url', 'events_url', 'followers_url', 'following_url', 'gists_url', 'gravatar_id', 'html_url', 'organizations_url', 'permissions', 'received_events_url', 'repos_url', 'site_admin', 'starred_url', 'subscriptions_url']
• Assignees
  ['avatar_url', 'events_url', 'followers_url', 'following_url', 'gists_url', 'gravatar_id', 'html_url', 'organizations_url', 'received_events_url', 'repos_url', 'site_admin', 'starred_url', 'subscriptions_url']
• Commits
  ['author', 'commit.verification', 'committer']
• Issues
  ['assignee', 'assignees', 'author_association', 'body', 'closed_at', 'comments', 'comments_url', 'created_at', 'events_url', 'html_url', 'labels', 'labels_url', 'locked', 'milestone', 'number', 'repository_url', 'state', 'title', 'url', 'user']

[nick-mccoy]

Added fields to 'reviews' in #18 and fields to 'pull_requests' in #13

[sminnee]

It's worth noting that if all these missing field were added that's a large volume of data with a lot of duplication, e.g. the detailed user metadata given on each commit. This notably affects issues, pull_requests, reviews