Add format check to actions (#668)

.github/workflows/cmake.yml

@@ -114,3 +114,9 @@ jobs:
       # Execute tests defined by the CMake configuration.  
       # See https://cmake.org/cmake/help/latest/manual/ctest.1.html for more detail
       run: ./test.sh -t
+
+    - name: Lint
+      if: runner.os == 'Linux'
+      working-directory: ${{env.GITHUB_WORKSPACE}}
+      shell: bash
+      run: ./format.sh && git diff --exit-code