Bump the version to 1.2.4

[Brollyy]

Release notes for 1.2.4:

New features

• Include info about Triple and Quadruple notes on a line by @Brollyy in https://github.com/PKBeam/Edda/pull/97
• Implement scroll wheel hold by @Brollyy in https://github.com/PKBeam/Edda/pull/103

Bugfixes

• Fixed a crash if the selected audio device is not plugged in by @Brollyy in https://github.com/PKBeam/Edda/pull/95
• Fixed a crash when trying to select a file cover.jpg for the map cover by @Brollyy in https://github.com/PKBeam/Edda/pull/96

Other

Note: Edda is now using .NET 8.0. You need to download the .NET 8.0 Runtime if you plan on using the NoRuntime executable. Edda is now released under a GPL-3.0 license

Once this version bump and the pending PR with scroll wheel hold are merged, I'll build the new executables and publish the release.