fix: bring back tests on external PRs (push doesn't cut it for forks)

.forgejo/workflows/test.yml

@@ -1,6 +1,6 @@
 name: Strudel tests
 
-on: [push]
+on: [push, pull_request]
 
 jobs:
   build:
@@ -19,7 +19,7 @@ jobs:
       - uses: actions/setup-node@v4
         with:
           node-version: ${{ matrix.node-version }}
-          cache: 'pnpm'
+          cache: "pnpm"
       - run: pnpm install
       - run: pnpm run format-check
       - run: pnpm run lint