Bump version to 0.5.0 and add notification features with cron support

[23f2005217]

This pull request introduces significant new features and improvements to the gcalendar tool, including desktop notifications for upcoming events, automated notifications via cron jobs, and enhanced logging. The changes also include a version bump to 0.5.0. Below are the most important updates grouped by theme:

New Features

• Desktop Notifications:

  • Added a --notify argument to send desktop notifications a specified number of minutes before an event. [1] [2]
  • Implemented the notify_events function in a new gcalendar/notification.py module to handle notifications and prevent duplicates.

• Automated Notifications with Cron:

  • Added --setup-cron and --remove-cron arguments to manage crontab entries for automated event checks and notifications. [1] [2] [3]
  • Implemented setup_crontab and remove_crontab functions to configure and remove cron jobs.

Documentation Updates

• Updated README.md to include usage instructions for the new --notify, --setup-cron, and --remove-cron options, along with examples for desktop and automated notifications.

Codebase Enhancements

• Logging:

  • Introduced logging configuration in the main function to improve debugging and error reporting.

• Version Update:

  • Incremented the version number from 0.4.1 to 0.5.0 in gcalendar/__init__.py.