Migrate from astyle to clang-format (#8464)

.github/workflows/pull-request.yml

@@ -238,11 +238,20 @@ jobs:
         python-version: '3.x'
     - name: Style check
       env:
+        LLVM_SNAPSHOT_KEY: "6084F3CF814B57C1CF12EFD515CF4D18AF4F7421"
         TRAVIS_BUILD_DIR: ${{ github.workspace }}
         TRAVIS_TAG: ${{ github.ref }}
       run: |
+          export GNUPGHOME=$(mktemp -d)
+          gpg --batch --keyserver keyserver.ubuntu.com --recv-keys "$LLVM_SNAPSHOT_KEY"
+          gpg --batch --armor --export "$LLVM_SNAPSHOT_KEY" | \
+            sudo tee /etc/apt/trusted.gpg.d/llvm-snapshot.gpg.asc
+          rm -r $GNUPGHOME
+          echo "deb http://apt.llvm.org/focal/     llvm-toolchain-focal-13   main" | \
+            sudo tee /etc/apt/sources.list.d/llvm.list
           sudo apt update
-          sudo apt install astyle
+          sudo apt install clang-format-13
+          pip3 install pyyaml
           bash ./tests/ci/style_check.sh