* 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)
These changes add a new flag to the various `ResourceOptions` types that
indicates that a resource should be deleted before it is replaced, even
if the provider does not require this behavior. The usual
delete-before-replace cascade semantics apply.
Fixes#1620.
* Delete Before Create
This commit implements the full semantics of delete before create. If a
resource is replaced and requires deletion before creation, the engine
will use the dependency graph saved in the snapshot to delete all
resources that depend on the resource being replaced prior to the
deletion of the resource to be replaced.
* Rebase against master
* CR: Simplify the control flow in makeRegisterResourceSteps
* Run Check on new inputs when re-creating a resource
* Fix an issue where the planner emitted benign but incorrect deletes of DBR-deleted resources
* CR: produce the list of dependent resources in dependency order and iterate over the list in reverse
* CR: deps->dependents, fix an issue with DependingOn where duplicate nodes could be added to the dependent set
* CR: Fix an issue where we were considering old defaults and new inputs
inappropriately when re-creating a deleted resource
* CR: save 'iter.deletes[urn]' as a local, iterate starting at cursorIndex + 1 for dependency graph
