Release v13.0

New Changes:

• Added icon compressor (make compress) and optimised svg icon (make prune)
• Added French translation (#33, #34) - Philipp Kiemle + A couple others
• Added build system checks to GitHub CI Pipeline
• Added comments for translators and tweaked translation strings (#36)
• Added bug report, feature request and pull request templates
• Added more documentation on build system targets and debugging (#38)
• Added code of conduct and contributing guidelines
• Fixed extension icon not showing up on some distros
• Use Gio.Settings to create GSettings objects
• Removed unused imports