Run tests on PR

Author: jmbaur

.github/workflows/ci.yaml

@@ -3,13 +3,15 @@ on:
   workflow_dispatch: # allows manual triggering
   push:
     branches:
-      - 'main'
+      - main
+  pull_request:
+    branches:
+      - main
 jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout repository
-        uses: actions/checkout@v4
-      - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@main
+      - uses: actions/checkout@v4
+      - uses: DeterminateSystems/nix-installer-action@main
+      - uses: DeterminateSystems/magic-nix-cache-action@main
       - run: nix flake check --print-build-logs