Build Cling with PR branch name

Get PR branch name from Github Actions event

.github/workflows/ci.yml

@@ -144,6 +144,7 @@ jobs:
         fi
       if: runner.os == 'macOS'
     - name: Execute cpt
+      if: github.event_name == 'pull_request'
       run: |
         if [[ "${{ matrix.compiler }}" = "gcc" && "${{ matrix.version }}" = "7" ]]; then
           export CLING_BUILD_FLAGS="-DCMAKE_CXX_STANDARD=17 -DCMAKE_CXX_STANDARD_REQUIRED=ON"
@@ -153,10 +154,10 @@ jobs:
         fi
         export CLING_BUILD_FLAGS="$CLING_BUILD_FLAGS -DCLANG_ENABLE_ARCMT=OFF -DCLANG_ENABLE_STATIC_ANALYZER=OFF -DLLVM_ENABLE_WARNINGS=OFF -DCLING_ENABLE_WARNINGS=ON"
         if [[ ${{ matrix.name }} == *"compile"* ]]; then
-          ./cpt.py -y --check-requirements --current-dev=tar --with-cmake-flags="$CLING_BUILD_FLAGS" --with-cling-url=https://github.com/$GITHUB_REPOSITORY --cling-branch=${GITHUB_REF##*/}
+          ./cpt.py -y --check-requirements --current-dev=tar --with-cmake-flags="$CLING_BUILD_FLAGS" --with-cling-url=https://github.com/$GITHUB_REPOSITORY --cling-branch=${{ github.head_ref }}
         elif [[ ${{ matrix.name }} == *"notar"* ]]; then
-          ./cpt.py -y --check-requirements --current-dev=tar --with-cmake-flags="$CLING_BUILD_FLAGS" --with-cling-url=https://github.com/$GITHUB_REPOSITORY --cling-branch=${GITHUB_REF##*/} --with-binary-llvm
+          ./cpt.py -y --check-requirements --current-dev=tar --with-cmake-flags="$CLING_BUILD_FLAGS" --with-cling-url=https://github.com/$GITHUB_REPOSITORY --cling-branch=${{ github.head_ref }} --with-binary-llvm
         else
-          ./cpt.py -y --check-requirements --current-dev=tar --with-cmake-flags="$CLING_BUILD_FLAGS" --with-cling-url=https://github.com/$GITHUB_REPOSITORY --cling-branch=${GITHUB_REF##*/} --with-binary-llvm --with-llvm-tar
+          ./cpt.py -y --check-requirements --current-dev=tar --with-cmake-flags="$CLING_BUILD_FLAGS" --with-cling-url=https://github.com/$GITHUB_REPOSITORY --cling-branch=${{ github.head_ref }} --with-binary-llvm --with-llvm-tar
         fi
       working-directory: tools/packaging/