Strip trailing spaces [ci skip]

tool/update-bundled_gems.rb

@@ -19,4 +19,5 @@ unless /^[^#]/ !~ (gem = $F[0])
   f = [gem.name, gem.version.to_s, uri, *$F[3..-1]]
   $_.gsub!(/\S+\s*/) {|s| (f.shift || "").ljust(s.size)}
   $_ = [$_, *f].join(" ") unless f.empty?
+  $_.rstrip!
 end