Validate that `required` metadata fields in `pom.xml` are populated in `analyze` step.

[This build](https://dev.azure.com/azure-sdk/internal/_build/results?buildId=5164784&view=results) was blocked unexpectedly due to:

- Project URL is not defined
- License information is missing
- SCM URL is not defined

It's the first time this package was being released, so this probably not a case of changing ESRP metadata requirements.

We should add some static analysis to `analyze` so that we can ensure these required fields are present, and devs won't be surprised at release time.