Properly set log level if —verbose flag is passed

There is no need to modify existing loggers since we are defining one
logging config. Setting the env var, invalidating the cache, and calling
setup_logging again are sufficient to set the log level properly at all levels.

Author: samdoran

src/lightspeed_stack.py

@@ -4,7 +4,6 @@
 main() function.
 """
 
-import logging
 import os
 from argparse import ArgumentParser
 
@@ -98,11 +97,8 @@ def main() -> None:
 
     if args.verbose:
         os.environ[LIGHTSPEED_STACK_LOG_LEVEL_ENV_VAR] = "DEBUG"
-        logging.getLogger().setLevel(logging.DEBUG)
-        for logger_name in logging.Logger.manager.loggerDict:
-            existing_logger = logging.getLogger(logger_name)
-            if isinstance(existing_logger, logging.Logger):
-                existing_logger.setLevel(logging.DEBUG)
+        setup_logging.cache_clear()
+        setup_logging()
 
     configuration.load_configuration(args.config_file)
     logger.info("Configuration: %s", configuration.configuration)