fix the encoding problem for subprocess.check_output

msg/tools/generate_microRTPS_bridge.py

@@ -253,7 +253,7 @@ else:
 ros2_distro = ""
 try:
     rosversion_out = subprocess.check_output(["rosversion", "-d"])
-    rosversion_out = rosversion_out.rstrip()
+    rosversion_out = rosversion_out.rstrip().decode('utf-8')
     if rosversion_out not in ["<unknown>", "kinetic", "lunar", "melodic"]:
         ros2_distro = rosversion_out
 except OSError as e: