Use alpine image for clang-format

.github/workflows/push.yml

@@ -103,28 +103,19 @@ jobs:
 
   check_formatting:
     runs-on: ubuntu-20.04
+    container:
+      image: alpine:3.15
 
     steps:
+      - name: deps
+        run: apk add --no-cache python3 py3-pip make git
+
       - uses: actions/checkout@v2
         with:
           submodules: true
 
-      - name: chmod
-        run: chmod +x setup.sh && chmod +x source/build.sh && sudo mkdir -p /build/cache && sudo chmod -R 777 /build
-
-      - name: Cached compiler source files
-        uses: actions/cache@v2.1.7
-        env:
-          cache-name: cache-compilers
-        with:
-          # we deliberately persist a cache folder forwards
-          path: /build/cache
-          key: ${{ runner.os }}-build-${{ env.cache-name }}
-          restore-keys: |
-            ${{ runner.os }}-
-
-      - name: setup
-        run: sudo apt-get update && sudo apt-get install -y make clang git python3 python3-pip && python3 -m pip install bdflib black flake8
+      - name: install black
+        run: python3 -m pip install bdflib black flake8
 
       - name: Check formatting with clang-format
         run: cd source && make clean && make check-style