AssemblyLevel attributes missing / inconsistent

[ericstj]

As mentioned in dotnet/runtime#108806 (comment) assemblies built from this repo are missing CLSCompliantAttribute

Also some other metadata attributes, NeutralResourcesLanguage, DefaultDllImportSearchPathsAttribute.
 
They are also missing some other centrally applied attributes. dotnet/runtime handles these here:
https://github.com/dotnet/runtime/blob/6d23f64952d0f242c4dcc7cbb230a619be930309/eng/versioning.targets#L11-L57

A good test would be to compare the attributes present on the netstandard2.0 assembly of the old package and new to see if anything important is missing. You can disassemble them with your tool of choice (ildasm, ILSpy, GenAPI, etc).

Here's a sample:

[ViktorHofer]

Fixed by #135