fix: deprecated alias of logger.warn #569

python-neovim fails to build with Python 3.13.0b1.

According to https://docs.python.org/3.13/whatsnew/3.13.html:

logging: Remove undocumented and untested Logger.warn() and
LoggerAdapter.warn() methods and logging.warn() function.  Deprecated
since Python 3.3, they were aliases to the logging.Logger.warning()
method, logging.LoggerAdapter.warning() method and logging.warning()
function.

pynvim/plugin/script_host.py

@@ -16,7 +16,7 @@
 
 
 logger = logging.getLogger(__name__)
-debug, info, warn = (logger.debug, logger.info, logger.warn,)
+debug, info, warn = (logger.debug, logger.info, logger.warning,)
 
 
 @plugin