fix(ruby): avoid mutating frozen string literals by replacing upcase! with upcase

Author: satoruk

Diff for: clients/algoliasearch-client-ruby/lib/algolia/transport/http/http_requester.rb

@@ -30,7 +30,7 @@ def send_request(host, method, path, body, query_params, headers, timeout, conne
         connection.options.open_timeout = connect_timeout / 1000
         path += handle_query_params(query_params)
 
-        @logger.info("Sending #{method.to_s.upcase!} request to #{path} with body #{body}") if ENV["ALGOLIA_DEBUG"]
+        @logger.info("Sending #{method.to_s.upcase} request to #{path} with body #{body}") if ENV["ALGOLIA_DEBUG"]
 
         response = connection.run_request(method, path, body, headers)