Audit check for gnome unstable as stable

Library/Homebrew/cmd/audit.rb

@@ -378,6 +378,15 @@ class FormulaAuditor
         problem "stable and devel versions are identical"
       end
     end
+
+    stable = formula.stable
+    if stable && stable.url =~ /#{Regexp.escape("ftp.gnome.org/pub/GNOME/sources")}/i
+      minor_version = stable.version.to_s[/\d\.(\d+)/, 1].to_i
+
+      if minor_version.odd?
+        problem "#{stable.version} is a development release"
+      end
+    end
   end
 
   def audit_patches