Check: lint Packit configuration as part of CI

This will ensure that our Packit config stays valid.

Signed-off-by: Tomáš Hozza <thozza@redhat.com>

.github/workflows/check.yml

@@ -45,6 +45,24 @@ jobs:
         severity: warning
         token: ${{ secrets.GITHUB_TOKEN }}
 
+  packit-config-lint:
+    name: "📦 Packit config lint"
+    runs-on: ubuntu-latest
+    container:
+      image: registry.fedoraproject.org/fedora:latest
+    steps:
+      - name: Install Packit
+        run: dnf -y install packit
+
+      - name: Check out code
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
+
+      - name: Validate Packit config
+        run: |
+          packit validate-config .packit.yaml
+
   snapshots:
     name: "🔍 Check for valid snapshot urls"
     runs-on: ubuntu-20.04