avoid double action for PRs, try turning on pnpm cache

.forgejo/workflows/test.yml

@@ -1,6 +1,6 @@
 name: Strudel tests
 
-on: [push, pull_request]
+on: [push]
 
 jobs:
   build:
@@ -17,7 +17,7 @@ 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