remote: upgrade Azure Blob storage version

[trallard]

Hi!

At the moment dvc[azure] has as a requirement azure = ["azure-storage-blob==2.1.0"]

Recently there Python SDKs were massively improved to be more Pythonic and efficient. I was wondering if it would be possible to allow for the use of the latest version (12.1). Or if there are any blockers for this I can help with?

[shcheklein]

@trallard I don't expect any major blockers and we would really appreciate a help with this! Could try to bump it up and see if we can run tests (create a PR from a fork)?