Fix logger

Author: esrakartalOpt

lib/optimizely/cmab/cmab_client.rb

@@ -158,7 +158,7 @@ def _do_fetch_with_retry(url, request_body, retry_config, timeout)
       rescue => e
         last_error = e
         if attempt < retry_config.max_retries
-          @logger.log(Logger::INFO, "Retrying CMAB request (attempt: #{attempt + 1} after #{backoff} seconds)...")
+          @logger.log(Logger::INFO, "Retrying CMAB request (attempt #{attempt + 1} after #{backoff} seconds)...")
           sleep(backoff)
           backoff = [backoff * (retry_config.backoff_multiplier**(attempt + 1)), retry_config.max_backoff].min
         end