Use verify-alpha-spec hook

[KyleFromNVIDIA]

With the deployment of rapids-build-backend, we need to make sure our dependencies have alpha specs.

Contributes to https://github.com/rapidsai/build-planning/issues/31

Description

Checklist

• [ ] I am familiar with the Contributing Guidelines.
• [ ] New or existing tests cover these changes.
• [ ] The documentation is up to date with these changes.