ci: add clang format to the actions

.github/workflows/ci.yml

@@ -35,6 +35,19 @@ jobs:
       - name: Run luacheck
         run: luacheck .
 
+  clang-format:
+    name: Clang Format
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Install Dependencies
+        run: sudo apt-get update && sudo apt-get install --no-install-recommends -y clang-format findutils
+
+      - name: Run clang format
+        run: find ./cpp -name "*.cpp" -o -name "*.hpp" | xargs clang-format -Werror --dry-run
+
   test:
     name: Build and test
     runs-on: ubuntu-latest