🔨 Rectified correct branch sourcing for ros2/demos in root Dockerfile.

Signed-off-by: Bey Hao Yun <[email protected]>

Dockerfile

@@ -17,7 +17,7 @@ WORKDIR /home/user/
 # Get ROS2 package image_tools available for sourcing.
 USER user
 RUN git clone https://github.com/ros2/demos.git \
-    --branch rolling_devel \
+    --branch rolling \
     --single-branch \
     --depth 1