Update release tagging instructions

Added instructions for pushing production branches during mainline releases.

Author: nathanielerowe

sbndcode_wiki/Tagging_a_release.md

@@ -107,7 +107,8 @@ Instructions
 
 -   Push everything to origin (once for sbndcode and once for sbndutil)
 
-        git push origin develop master
+        git push origin develop master # if mainline release
+		git push origin production/sbnd-gen2 production/sbnd-gen2-master # if mainline release
         git push --tags