title: .NET Core 2.0 Docker image missing and backwards compatibility
body: <p>2 Days ago my 2.0 .net Core project stopped building the Docker image. I can't find any news about that so i'm guessing it's because the version is out of support from a long time ago, so they just removed it?</p>
  <p>Also i am finding mixed responses about backwards compatibility. Is a .net 2.1 docker image compatible with a 2.0 project?</p>
  <p>I am receiving the following error:</p>
  <pre><code>[1/4] FROM mcr.microsoft.com/dotnet/aspnet:2.0
  resolve mcr.microsoft.com/dotnet/aspnet:2.0 0.1s done
  ERROR: mcr.microsoft.com/dotnet/aspnet:2.0 not found
  [internal] load metadata for mcr.microsoft.com/dotnet/aspnet:2.0:
   [1/4] FROM mcr.microsoft.com/dotnet/aspnet:2.0:
   failed to solve with frontend dockerfile.v0: failed to build LLB: failed to load cache key: mcr.microsoft.com/dotnet/aspnet:2.0 not found
  </code></pre>