Related to the error above: if you are using Azure NextGen with .NET, please upgrade your Pulumi CLI to 2.13.0+

And an extra note to this. It seems like pulumi is a pre-installed tool on at least AzureCLI, so to use it there you need to run something like:

curl -fsSL <https://get.pulumi.com> | bash
      export PATH=$HOME/.pulumi/bin:$PATH
      echo "##vso[task.setvariable variable=path]$PATH"

That will install the latest version and add that version to the path BEFORE the already installed version of pulumi.