handling issues resource more efficiently

[tomasohCHOM]

GitHub's REST API does not seem to aggregate number of issues in a way that it can separate issues from pull requests (at the end of the day, pull requests are a type of issue).

We are currently fetching the number of issues and pull requests by manually iterating through each, then using the issue.is_issue property to see whether it is an issue or a pull request. This is obviously very inefficient, and now that acmcsuf.com is part of this org (with 1000+ issues/PRs), it's unfeasible to grab these values from just the REST API.

We can do two things to address this:

• Use GitHub's GraphQL API, which seems to be more flexible with queries and can help us get out the responses much faster.
• Use repo.get_pulls to grab the number of PRs first, then get the issue count by subtracting it from totalCount (this might be OK actually)

[timothyouu]

accidentally closed, but reopened 😄