[util][bin/repo] Fix for ruby 3.3

bin/repo

@@ -80,7 +80,7 @@ module Repo
   def self.tags(comments)
     tags = nil
     for line in comments
-      if line =~ /^[\s\t#]*tags:[\s\t]*([\w,\s\.\d]+)/i
+      if line.first.to_s =~ /^[\s\t#]*tags:[\s\t]*([\w,\s\.\d]+)/i
         tags = $1.strip
         break
       end