Checkout code and sync submodules (on new branch, might have new submodules.)

Author: jonpugh

.github/workflows/operations.site.deploy.ddev.yml

@@ -144,6 +144,8 @@ jobs:
             run-with-summary git clone --recursive ${{ inputs.git_repository }} ${{ inputs.git_root }}
           fi
           cd ${{ inputs.git_root }}
+          git checkout --force ${{ inputs.git_ref }}
+          git submodule sync --recursive
 
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