opm registry add doesn't detect dependencies.yaml problems

[cdjohnson]

See operator-framework/operator-lifecycle-manager#1770 for details.

Summary:

When using opm registry add or opm index add

1. When the schema format of dependencies.yaml is invalid, there is no error or warning.
2. When the semver range syntax is invalid, there is no error or warning.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[exdx]

The semver version field syntax may not be documented properly.

The incorrect dependencies.yaml formatted file may be passed along just as additional data.