v3.3.0-rc1 - First release candidate for v3.3.0

This release contains many quality of life improvements and comes with a new design.
The release candidate is issues to test the new version (and build infrastructure) before the final release.

Changes since v3.2.0

• The application can now automatically update itself.
• Notifications for received files now mentions where the file was saved to.
• Present more useful information about how to write custom codes.
• The dialog for custom codes now focuses the text entry automatically.
• The selection of the download path has been reworked to be more useful.
• Minor redesign of the send and receive tabs.
• Minor wording improvements inside the settings tab.
• Updated fyne to v2.3.0.
  • An entirely new theme with improved visuals.
  • The application will now follow the FreeDesktop Dark Style Preference on Linux/BSD.
  • Added an option to create a new folder within the folder selection dialog.
  • Lots of other improvements and fixes.
• Update compress to v1.15.14.
  • Includes performance improvements that benefit sending and receiving of directories.
• Fixed application icon being bundled twice.
• Minimal supported Go compiler version is now Go 1.17.