[Bug] or [Features] az repos policy approver-count

`az repos policy approver-count` `create` and `update` is missing the settings:

First it prevent us from setting it from AZ CLI and if we try to update an existing policy it will reset missing settings that was set from web site or other tools.

**Describe the solution you'd like**

https://docs.microsoft.com/en-us/cli/azure/ext/azure-devops/repos/policy/approver-count?view=azure-cli-latest#ext_azure_devops_az_repos_policy_approver_count_create
and
https://docs.microsoft.com/en-us/cli/azure/ext/azure-devops/repos/policy/approver-count?view=azure-cli-latest#ext_azure_devops_az_repos_policy_approver_count_update
gets a new Optional Parameters
called `blockLastPusherVote`

**Additional context**
It would be an idea to change the update to a PATCH request instead of a PUT.
So it does not override settings az cli dont know about.
Note: It require that https://docs.microsoft.com/en-us/rest/api/azure/devops/policy/configurations/update?view=azure-devops-rest-6.0 will be update to support PATCH request.