This app prevents you from merging PRs which don't meet certain criteria. To configure, simply install the app and create a file under .github/pr_labels.yml

version: '1'
invalidStatus: "pending"
labelRule:
  endsWith:
    - "g"
  values:
    - "bug"
    - "enhancement"

See docs for more info

This app is free for public repositories, where as you'll need a paid subscription for private repositories, you can set the checks status using the invalidStatus, and it supports endsWith, startsWith and values options.