Cache prek hook environments in CI

.github/workflows/matrix.yml

@@ -28,6 +28,12 @@ jobs:
       - name: Check out
         uses: actions/checkout@v6
 
+      - name: Restore prek cache
+        uses: actions/cache@v4
+        with:
+          path: var/prek
+          key: arch-prek-v1-${{ hashFiles('.pre-commit-config.yaml') }}
+
       - name: Install dependencies
         run: pacman -S --noconfirm --needed just mise python