BLD: Add note about keeping jobs in sync

Author: agriyakhetarpal

.github/workflows/unit-tests.yml

@@ -347,6 +347,7 @@ jobs:
       - name: Run Tests
         uses: ./.github/actions/run-tests
 
+  # NOTE: this job must be kept in sync with the Pyodide build job in wheels.yml
   emscripten:
     # Note: the Python version, Emscripten toolchain version are determined
     # by the Pyodide version. The appropriate versions can be found in the