Change CI to run test checks on ALL commits?

[kdmukai]

cc: @dbast

Our current repo only runs the CI test suite check on PR updates and merges to dev or main.

But there should be no difference if it's changed to run on ALL commits because dev and main only ever see PR merges. Only @newtonick and @SeedSigner have permissions to push commits but Nick makes his changes in his own fork and SeedSigner (the man) is not an active dev anymore (obv he's still a key participant in other ways).

Background

I want my SeedSigner fork to kick off the CI test suite checks on EVERY commit for ANY branch.

I'm a Github Actions noob, but successfully made this change in one of my branches:

https://github.com/kdmukai/seedsigner/commits/local_kdmukai_ci/

But it occurs to me that I'd need to have this mod in all of my branches to get this desired behavior. But then it'll be a mess to pull that CI yaml change out before PRing a branch upstream.

As I thought this through, I landed at the reasoning at the very top: Just enable CI test checks on every commit. Zero actual impact on the upstream repo, more feedback for devs working in their forks.