Drop Microsoft.AspNetCore.Http.Abstractions for netcoreapp3.1 and higher

[trejjam]

Changes

This PR handle issue with dependency restoring for .NetCore 3.1 and higher. There is no Microsoft.AspNetCore.Http.Abstractions after .NetCore 2.2. The Http.Abstraction requires other v2.x packages, which causes resolving issues for newer frameworks.

[CodeBlanch]

@trejjam This is an interesting idea! I have only seen the end-of-line applications reference Microsoft.AspNetCore.App. Is this a common thing done by libraries? Do you have any favorite examples doing the same thing we could check out?

[trejjam]

The oldest I know are serilog/serilog-aspnetcore#165 or https://github.com/toddams/RazorLight/blob/master/src/RazorLight/RazorLight.csproj

[cijothomas]

.NET has published guidelines on this here : https://docs.microsoft.com/en-us/aspnet/core/fundamentals/target-aspnetcore?view=aspnetcore-5.0&tabs=visual-studio

[cijothomas]

@trejjam Sorry for coming back so late. Would you have time to resolve the conflicts in this PR, so we can take this forward? the change looks good and is in alignment with that .NET guidelines.

[trejjam]

Yes, I will resolve it.

[trejjam]

@cijothomas Done

[trejjam]

Hello @cijothomas, can you review it?

[codecov]

Codecov Report

Merging #1917 (0df928d) into main (db6dc75) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #1917   +/-   ##
=======================================
  Coverage   85.10%   85.10%           
=======================================
  Files         187      187           
  Lines        6075     6075           
=======================================
  Hits         5170     5170           
  Misses        905      905           

Impacted Files	Coverage Δ
...ion.AspNetCore/AspNetCoreInstrumentationOptions.cs	100.00% <ø> (ø)
...tation.AspNetCore/Implementation/HttpInListener.cs	86.42% <ø> (ø)
...Telemetry/Internal/SelfDiagnosticsEventListener.cs	95.34% <0.00%> (-0.78%)	⬇️
...penTelemetry/Internal/ServiceProviderExtensions.cs	100.00% <0.00%> (+33.33%)	⬆️