Add formatting action

Author: fmeum

.github/workflows/check-formatting.yml

@@ -0,0 +1,41 @@
+name: Check formatting
+
+# Controls when the action will run.
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+  workflow_dispatch:
+
+jobs:
+  check_formatting:
+    runs-on: ubuntu-20.04
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Setup Go environment
+        uses: actions/setup-go@v2
+        with:
+          go-version: '^1.15.5'
+
+      - name: Install formatters
+        run: |
+          wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
+          sudo apt-get install software-properties-common
+          sudo add-apt-repository 'deb http://apt.llvm.org/focal/ llvm-toolchain-focal-11 main'
+          sudo apt-get install clang-format-11
+          curl -sSLO https://github.com/pinterest/ktlint/releases/download/0.40.0/ktlint && chmod a+x ktlint && sudo mv ktlint /usr/bin/ktlint
+          go get -u github.com/google/addlicense
+          go get github.com/bazelbuild/buildtools/buildifier
+
+      - name: Run format.sh and print changes
+        run: |
+          ./format.sh
+          clang-format --version
+          git diff
+
+      - name: Check for changes
+        run: "[ $(git status --porcelain | wc -l) -eq 0 ]"