Can't install dotnet 6 SDK.

[AliveNeko]

vfox version: vfox version 0.6.0
dotnet plugin version:

Plugin Info:
Name     -> dotnet
Version  -> 0.1.1
Homepage -> https://github.com/version-fox/vfox-dotnet
Desc     ->
dotnet plugin, support for dotnet sdks 6.0, 7.0, 8.0
Legacy Files -> None
Notes:
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I have a old project using dotnet 6, but I can't install dotnet6 SDK by dotnet plugin.

Is this a bug？

[sgpublic]

It looks like this plugin gets the available version from the official download page and dotNet 6.0 has reached end of support, that’s why this plugin cannot install dotNet 6.0.

[aooohan]

fix by #4