* Hook into pmpro_registered_crons to add PBC crons to site health info

[MaximilianoRicoTabo]

All Submissions:

• Have you followed the Contributing guidelines?
• Does your code follow the WordPress' coding standards?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes proposed in this Pull Request:

Hook into pmpro_registered_crons to add PBC crons to site health info
Resolves #124 .

How to test the changes in this Pull Request:

Pull site health info and observe that crons are there

Other information:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you successfully run tests with your changes locally?

Changelog entry

Enter a summary of all changes on this Pull Request. This will appear in the changelog if accepted.

[MaximilianoRicoTabo]

@kimwhite FYI