Add build directory string to codeql.yml

.github/workflows/codeql.yml

@@ -58,6 +58,13 @@ jobs:
         cache-key-prefix: ${{ runner.os }}-Qt-Cache-${{ env.QT_VERSION }}
         dir: ${{ github.workspace }}/Qt
 
+    - name: Set reusable strings
+      # Turn repeated input strings (such as the build output directory) into step outputs. These step outputs can be used throughout the workflow file.
+      id: strings
+      shell: bash
+      run: |
+        echo "build-output-dir=${{ github.workspace }}/build" >> "$GITHUB_OUTPUT"
+
     - name: Configure CMake
       env:
         CMAKE_PREFIX_PATH: ${{env.Qt6_DIR}}