Previous tags like azure-appconfiguration_1.0.0 that we leverage to test "the world as it was" against the latest version of azure-core, hit some major bumps with the dependency on mgmt-resources.

This PR made azure-sdk-tools compatible with azure-mgmt-resources and azure-mgmt-keyvault track1/track2. However, since we use tools "as they were" in the checked-out tag that we're testing against, we need to either

1. Pin deps on azure-mgmt-keyvault<7.0.0
2. add msrestazure as a dev_req

I have a PR over here that does #2. I'm dis-satisfied and would like a to implement a better solution that's more future proof.