Fix syntax

Author: walbourn

.github/workflows/main.yml

@@ -83,9 +83,9 @@ jobs:
         arch: ${{ matrix.arch }}
 
     - name: 'Configure CMake'
-      working-directory: ${{env.GITHUB_WORKSPACE}}
+      working-directory: ${{ github.workspace }}
       run: cmake --preset=${{ matrix.build_type }}
 
     - name: 'Build'
-      working-directory: ${{env.GITHUB_WORKSPACE}}
+      working-directory: ${{ github.workspace }}
       run: cmake --build out\build\${{ matrix.build_type }}