fix: change GH workflows to run on all PR updates

[adamalton]

After much experimentation, I have concluded that:

• The reason why the CI linting was flagging lines of code that didn't exist in the PR branch but only existed in main is because GH Actions does a prospective merge before running the scripts, so any issues in main show up in the CI run in the PR.
  • Now that we've fixed the linting issues in main, this isn't a problem.
• Removing aegir and replacing its linting with standard isn't worth the hassle (aegir is too tightly bound to various bits of the project setup, and other than parity with the web3.storage repo, we wouldn't gain much by switching).

So the only thing I've changed in this PR is the triggers, so that the CI should now run for any PR, even if it's merging into a feature branch rather than main. That's it. Long journey. Small PR.

[joshJarr]

Awesome stuff! Really good find, I thought I was going mad after seeing the same linting errors across many PRs!