Create pr-format-check.yml action (#70)

* Create pr-format-check.yml

.github/workflows/pr-format-check.yml

@@ -0,0 +1,32 @@
+on:
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  clang_format_check:
+    name: Check Clang Format
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+
+      - name: Set up clang-format
+        run: sudo apt-get install clang-format -y
+
+      - name: Fetch main branch
+        run: git fetch origin main:main
+
+      - name: Check code formatting
+        id: check_formatting
+        run: |
+          git clang-format --style=file:firmware/.clang-format --diff $(git merge-base HEAD main) -v > clang_format_output.txt
+          if grep -q "clang-format did not modify any files" clang_format_output.txt; then
+            echo "Code formatting is already correct."
+          elif grep -q "Running clang-format on the following files" clang_format_output.txt; then
+            echo "Code formatting changes detected."
+            exit 1
+          fi