Merge pull request #4720 from ros-infrastructure/gazebo9.3.1

[gazebo] 9.3.0 -> 9.3.1

library/gazebo

@@ -94,10 +94,10 @@ Directory: gazebo/8/ubuntu/xenial/libgazebo8
 
 Tags: gzserver9, gzserver9-xenial
 Architectures: amd64
-GitCommit: 8639dbf1ee782ea44b7990db3e69781cfabfad1d
+GitCommit: 59f76a64533a9c352b03919172ce0783bd1e583e
 Directory: gazebo/9/ubuntu/xenial/gzserver9
 
 Tags: libgazebo9, libgazebo9-xenial, latest
 Architectures: amd64
-GitCommit: 8639dbf1ee782ea44b7990db3e69781cfabfad1d
+GitCommit: 59f76a64533a9c352b03919172ce0783bd1e583e
 Directory: gazebo/9/ubuntu/xenial/libgazebo9