reducing the dep version to 4.7.0 (#47)

[iamsgarg-ob]

What is the change in this PR?

• In order to support azure key vault for @secrets, we used the 4.8.0 az-keyvault-secrets library. However this conflicts with the azure-cli package which is still dependent on the 4.7.0 az-keyvault-secrets

Darwin Linux Windows

Without this PR - installing metaflow + azure-cli will conflict with each other. The Integration of az-key-vault works as intended with 4.7.0 as well.

Hence this PR is not going to cause any unintended consequences.