audit: don't warn about tarball in non-GitHub URL.

Library/Homebrew/cmd/audit.rb

@@ -267,7 +267,7 @@ class FormulaAuditor
     end
 
     # Use new-style archive downloads
-    urls.select { |u| u =~ %r[https://.*/(?:tar|zip)ball/] && u !~ %r[\.git$] }.each do |u|
+    urls.select { |u| u =~ %r[https://.*github.*/(?:tar|zip)ball/] && u !~ %r[\.git$] }.each do |u|
       problem "Use /archive/ URLs for GitHub tarballs (url is #{u})."
     end