Add lint workflow for GitHub actions

.github/workflows/lint.yml

@@ -0,0 +1,12 @@
+name: lint
+on: [push, pull_request]
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v1
+    - uses: DoozyX/clang-format-lint-action@v0.5
+      with:
+        source: '.'
+        extensions: 'h,c,cpp'
+        clangFormatVersion: 9