sdformat12: revision bump rebuild for abseil

Author: scpeters

Formula/sdformat12.rb

@@ -4,7 +4,7 @@ class Sdformat12 < Formula
   url "https://osrf-distributions.s3.amazonaws.com/sdformat/releases/sdformat-12.8.0.tar.bz2"
   sha256 "5c0d6579738ff14f849f8d6e101468a8f0abc43000b2b8040170fe082a630489"
   license "Apache-2.0"
-  revision 6
+  revision 7
 
   head "https://github.com/gazebosim/sdformat.git", branch: "sdf12"