gz-sim9: revision bump rebuild

Author: scpeters

Formula/gz-sim9.rb

@@ -4,7 +4,7 @@ class GzSim9 < Formula
   url "https://osrf-distributions.s3.amazonaws.com/gz-sim/releases/gz-sim-9.0.0.tar.bz2"
   sha256 "62effba56ffbfdb2db67b6ccca17527df0ede7fa83469df72c2f043f6cc96ea8"
   license "Apache-2.0"
-  revision 3
+  revision 4
 
   head "https://github.com/gazebosim/gz-sim.git", branch: "gz-sim9"