Assets file '/home/runner/work/neo-devpack-dotnet/neo-devpack-dotnet/src/Neo.SmartContract.Testing/obj/project.assets.json' doesn't have a target for 'netstandard2.1'. Ensure that restore has run and that you have included 'netstandard2.1' in the TargetFrameworks for your project.

Assets file '/home/runner/work/neo-devpack-dotnet/neo-devpack-dotnet/src/Neo.SmartContract.Testing/obj/project.assets.json' doesn't have a target for 'netstandard2.1'. Ensure that restore has run and that you have included 'netstandard2.1' in the TargetFrameworks for your project.

Process completed with exit code 1.

Dereference of a possibly null reference.