Add back missing NET6+ targets to AngleSharp.nuspec

[lahma]

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Description

While there's still ongoing discussion about pros and cons for using csproj instead of nuspec file on #1189 I think it's better to fix what I broke as an intermediate solution. Bringing back explicit dependency targets without the actual dependencies.

[lahma]

Another food for thought, NET 7 will be obsolete next month so how long should that be supported as an explicit target.

[FlorianRappl]

Thanks for spotting this!

[FlorianRappl]

Another food for thought, NET 7 will be obsolete next month so how long should that be supported as an explicit target.

As long as we can (i.e., as long as it does not "hurt" / limit us) - but same as with .NET 4.6.1 if we ever encounter even the slightest problem we'd remove it.

[lahma]

Another food for thought, NET 7 will be obsolete next month so how long should that be supported as an explicit target.

As long as we can (i.e., as long as it does not "hurt" / limit us) - but same as with .NET 4.6.1 if we ever encounter even the slightest problem we'd remove it.

Yep, I think the pain starts to hit if GH Actions runners start to drop obsolete targeting.