Update comment

Author: jdetter

.github/workflows/csharp-test.yml

@@ -162,6 +162,7 @@ jobs:
           key: Unity-${{ github.head_ref }}
           restore-keys: Unity-
 
+        # We need this to support "Docker in Docker"
       - name: Start Docker daemon
         run: /usr/local/bin/start-docker.sh
       - name: Run Unity tests