Better commit/changelog validation when using Github

[daviddavis]

When using Github issues, towncrier is able to link changelog entries to the PR. So having an issue for each PR is less essential. We should allow the changelog to use the PR #. Check out this simple example from towncrier where 338 is the PR #.

Current validation

Today, the current validation is:

• Check if the commit references any issues
  • If so, check that the issues are open and have changelog files in the CHANGES directory
• Else, check if the commit has [noissue] in it
  • If not, fail the check

Proposal

I'd propose we modify the current behavior a bit:

• Check if the commit references any issues
  • If so, check that the issues are open and have changelog files in the CHANGES directory
• Else, check if the commit has [noissue] in it
  • If not, check that there's a changelog for the current PR #
    • If there's no changelog entry, fail the build

This would allow us to not have to specify [noissue] in cases where there's no issue but we still have a changelog entry which corresponds to the PR #.

[stale]

This issue has been marked 'stale' due to lack of recent activity. If there is no further activity, the issue will be closed in another 30 days. Thank you for your contribution!