logging: improve default logging format (issue5214)

We improve the following things in the logging format:

  * Show module name instead of just the filename
  * show level of logging as the first thing
  * show lineno attached to module:file details

Thanks to @blueyed who suggested this on the github issue.

It's my first contribution and I have added myself to AUTHORS.

I also added to a changelog file.

src/_pytest/logging.py

@@ -15,7 +15,7 @@ from _pytest.compat import dummy_context_manager
 from _pytest.config import create_terminal_writer
 from _pytest.pathlib import Path
 
-DEFAULT_LOG_FORMAT = "%(filename)-25s %(lineno)4d %(levelname)-8s %(message)s"
+DEFAULT_LOG_FORMAT = "%(levelname)-8s %(name)s:%(filename)s:%(lineno)d %(message)s"
 DEFAULT_LOG_DATE_FORMAT = "%H:%M:%S"