clang-check in ci

.github/workflows/build_check.yml

@@ -54,3 +54,15 @@ jobs:
         with:
           name: firmware
           path: .pio/build/lora_board/firmware.bin
+
+  formatting-check:
+    name: Formatting Check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Run clang-format style check for C/C++ programs.
+        uses: jidicula/clang-format-action@v3.2.0
+        with:
+          clang-format-version: '11'
+          check-path: 'src'
+