lib/fog/aws/signaturev4.rb in fog-aws-3.22.0 vs lib/fog/aws/signaturev4.rb in fog-aws-3.23.0

@@ -104,10 +104,10 @@
         end
         canonical_query_string.join("&")
       end
 
       def canonical_headers(headers)
-        canonical_headers = ''
+        canonical_headers = +''
 
         for key in headers.keys.sort_by {|k| k.to_s.downcase}
           canonical_headers << "#{key.to_s.downcase}:#{headers[key].to_s.strip}\n"
         end
         canonical_headers