chore: Run test workflow on PRs (#81)

Author: Varpuspaavi

.github/workflows/test.yml

@@ -1,10 +1,10 @@
 name: Test
-on: [ push ]
+on: [push, pull_request]
 jobs:
   test:
     strategy:
       matrix:
-        ruby: [ 3.1, 3.2 ]
+        ruby: [3.1, 3.2]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4