Change 'ROS2' to 'ROS 2' in README (#2235) (#2236)

(cherry picked from commit 3ec9086)

Signed-off-by: Christophe Bedard <[email protected]>
Co-authored-by: Christophe Bedard <[email protected]>

Author: mergify[bot]

README.md

@@ -358,7 +358,7 @@ output_bags:
 
 When starting a recording or playback, you can pass a YAML file that contains QoS profile settings for a specific topic.
 The YAML schema for the profile overrides is a dictionary of topic names with key/value pairs for each QoS policy.
-Below is an example profile set to the default ROS2 QoS settings.
+Below is an example profile set to the default ROS 2 QoS settings.
 
 ```yaml
 /topic_name: