chore: Rerun tree-shaking tests when a PR is updated

[iwoplaza]

It seems like the tree-shaking test is run only once, when the PR is created, not on every change, making it stale.

[pullfrog]

  ^{｜ Build this ➔ ｜ Make a plan ➔}

[aleksanderkatan]

I'm pretty sure it works just fine

Can you link a PR where it didn't work?