Update cmake-single-platform.yml

Author: ewanwm

.github/workflows/cmake-single-platform.yml

@@ -19,7 +19,6 @@ jobs:
     # See: https://docs.github.com/en/free-pro-team@latest/actions/learn-github-actions/managing-complex-workflows#using-a-build-matrix
     runs-on: ubuntu-latest
 
-    steps:
     steps:
     # this Action should follow steps to set up Python build environment
     - name: Install Python dependencies