[BUG] OpenTabletDriver needs .NET 6, spec requires .NET 8

[Hexality]

Describe the bug
OpenTabletDriver complains about not having .NET6.0 runtime installed when it was supposed to be upgraded to .NET8.0.

To Reproduce

1. Install '.NET 8.0 and OpenTabletDriver'
2. See error 'NETCore.App 6.0 not found'

Expected behavior
Run OTD with .NET 8.0 Runtime and/or SDK without having to rely on .NET 6.0 Runtimes and/or SDK.

Affected (please complete the following information):

• Ultramarine 40
• OpenTabletDriver v0.6.4.0+9f4e357910a5917ef86166c195c858c1c65b46d2

Additional context
.NET 6.0 has conflicting problems with .NET 8.0 (which I have talked about in #general chat of FyraLabs discord server), because of that migrating OTD to 8.0 was expected. However, today after I removed .NET 6 so I could update everything, OTD still complained about not having .NET 6.0 installed.

[linear]

FYRA-75 [BUG] OpenTabletDriver on Terra 40 still requires dotnet-runtime-6.0

[madonuko]

Seems to be caused by the fact that it hasn't had a new release since Dec 2023. Should actually make this a nightly package.

[korewaChino]

Actually seems like .NET 8.0 can compile code for .NET 6.0 so maybe let's just add .NET 6.0 as a runtime dependency, this seems to be the case here since OTD is written with 6.0 in mind

[korewaChino]

Okay, update: Seems like upstream is only supporting .NET 6.0 for now, so our solution is to simply just change the dotnet runtime to 6.0