Fix clang-format CI check

azure-pipelines/clang-format-applied.yml

@@ -20,9 +20,9 @@ stages:
     steps:
     - bash: |
         wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
-        sudo apt-add-repository "deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic main"
+        sudo apt-add-repository "deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-12 main"
         sudo apt-get update
-        sudo apt-get install -y clang-format
+        sudo apt-get install -y clang-format-12
       displayName: 'Install clang-format'
     - bash: |
         # Checkout the master branch as we require it to get the list of modified files