Adds initial support for resource methods (via a new `Call` gRPC method similar to `Invoke`), with support for authoring methods from Node.js, and calling methods from Python.
* Make `async:true` the default for `invoke` calls (#3750)
* Switch away from native grpc impl. (#3728)
* Remove usage of the 'deasync' library from @pulumi/pulumi. (#3752)
* Only retry as long as we get unavailable back. Anything else continues. (#3769)
* Handle all errors for now. (#3781)
* Do not assume --yes was present when using pulumi in non-interactive mode (#3793)
* Upgrade all paths for sdk and pkg to v2
* Backport C# invoke classes and other recent gen changes (#4288)
Adjust C# generation
* Replace IDeployment with a sealed class (#4318)
Replace IDeployment with a sealed class
* .NET: default to args subtype rather than Args.Empty (#4320)
* Adding system namespace for Dotnet code gen
This is required for using Obsolute attributes for deprecations
```
Iam/InstanceProfile.cs(142,10): error CS0246: The type or namespace name 'ObsoleteAttribute' could not be found (are you missing a using directive or an assembly reference?) [/Users/stack72/code/go/src/github.com/pulumi/pulumi-aws/sdk/dotnet/Pulumi.Aws.csproj]
Iam/InstanceProfile.cs(142,10): error CS0246: The type or namespace name 'Obsolete' could not be found (are you missing a using directive or an assembly reference?) [/Users/stack72/code/go/src/github.com/pulumi/pulumi-aws/sdk/dotnet/Pulumi.Aws.csproj]
```
* Fix the nullability of config type properties in C# codegen (#4379)
This commit will introduce the ability to load providers in `query`
mode.
Previously, `query` mode has been effectively a stand-alone execution
environment for language hosts, running without (e.g.) the
`StepExecutor` and similar engine facilities, but with some minimal
constructs hooked up, notably the ability to retrieve stack snapshots
from the backend for querying.
This commit extends this functionality somewhat by allowing `query` to
load Pulumi resource providers, and to run `Invoke` on them. This will
allow us, in the future, to "query" resource providers in the same way
we can query stack snapshots.
