chore: lint PR titles/commit messages in the CI

[JGAntunes]

After #285 releases are now made using release-please. This however depends on enforcing conventional-commits on everything that lands on the main branch. For PRs this means linting both commit messages as well as the PR title - https://github.community/t/how-to-change-the-default-squash-merge-commit-message/1155. It would probably be a good idea to have an action validating this 👍

[mraerino]

if we're able to find something that just enforces the PR title it would be nice, b/c

• it's easy for people to change it
• if we squash, single commits don't matter
• we can allow squashing as the only allowed merge method

@erezrokah found this: https://github.com/marketplace/actions/conventional-pr-title

[mraerino]

this one seems good: https://github.com/amannn/action-semantic-pull-request

[JGAntunes]

@mraerino I'm not 100% sure linting only PR titles will cover it, as I believe the default behaviour for PRs with a single commit when squashed is to use the commit msg of that single commit and not the PR title:

• https://github.community/t/how-to-change-the-default-squash-merge-commit-message/1155
• Did a little experiment of my own - nop JGAntunes/actions-playground#3 - landed as - JGAntunes/actions-playground@7231e1a - in the main branch once merged.

I've seen this action for example handles that case - https://github.com/beemojs/conventional-pr-action/blob/master/src/index.ts#L171 - but haven't tried it yet.

[mraerino]

yeah, with that check it's definitely nicer!

[JGAntunes]

A conventional commit lint app should now be enabled for this repo - https://github.com/apps/conventional-commit-lint-gcf/installations/14413148 - once everyone's is comfortable with it we could make it a required step in our CI pipeline 👍