feat(ci): Run clang-format to check files.

.clang-format

@@ -0,0 +1,4 @@
+BasedOnStyle: LLVM
+IndentWidth: 4
+ColumnLimit: 100
+SortIncludes: false

.github/workflows/clang-format-lint.yml

@@ -0,0 +1,25 @@
+name: clang-format-lint
+
+on:
+  push:
+    paths:
+      - "app/boards/**/*.c"
+      - "app/include/**/*.h"
+      - "app/src/**"
+  pull_request:
+    paths:
+      - "app/boards/**/*.c"
+      - "app/include/**/*.h"
+      - "app/src/**"
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    name: clang-format lint
+
+    steps:
+      - uses: actions/checkout@v2
+      - uses: DoozyX/clang-format-lint-action@v0.9
+        with:
+          source: "./app"
+          extensions: "h,c"