Add shell command back

.github/workflows/codeql.yml

@@ -75,10 +75,14 @@ jobs:
     # ℹ️ Command-line programs to run using the OS shell.
     # 📚 See https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#jobsjob_idstepsrun
     - if: matrix.build-mode == 'manual'
-    - name: Setup .NET Core
-      uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: '3.1'
+      shell: bash
+      run: |
+        echo 'If you are using a "manual" build mode for one or more of the' \
+          'languages you are analyzing, replace this with the commands to build' \
+          'your code, for example:'
+        echo '  make bootstrap'
+        echo '  make release'
+        exit 1
 
     - name: Perform CodeQL Analysis
       uses: github/codeql-action/analyze@v3