Add a Lock event 'sso login'

[countergram]

Changes

This extends the existing event emitter pattern with a new event, called sso login (casing & spacing follows the existing federated login event name for social).

Our current use case for this is to make some adjustments (which have to be pre-login) based on our enterprise clients with their own IdPs logging in by doing our own lookup of the client's configuration.

References

This will help with a support ticket on my company's account: https://support.auth0.com/tickets/00439926

Testing

The existing npm run test:cli passes. I do not see any unit test cases currently existing for event emitters such as federated login so it doesn't appear to be a pattern now. I don't have access to Saucelabs to run the default npm test.

Checklist

• I have read the Auth0 general contribution guidelines
• I have read the Auth0 Code of Conduct
• All existing and new tests complete without errors
• All code quality tools/guidelines have been run/followed
• All relevant assets have been compiled
• All active GitHub checks have passed

[joshcanhelp]

@countergram - Appreciate the contribution here! From a code standpoint, it looks fine but I want to pass it by the primary maintainers here to make sure an additional event makes sense.

Stay tuned!