update jmeVersion to 3.3.1 in gradle.properties

Author: stephengold

gradle.properties

@@ -1,5 +1,5 @@
 # Version number: Major.Minor.SubMinor (e.g. 3.3.0)
-jmeVersion = 3.3.0
+jmeVersion = 3.3.1
 
 # Leave empty  to autogenerate
 # (use -PjmeVersionName="myVersion" from commandline to specify a custom version name )