Standardize values and type of outcome

[xbcsmith]

Changes

Submitter Checklist

As the author of this PR, please check off the items in this checklist:

• [ ] Has the primer doc been updated if a design decision is involved
• [ ] Have the JSON schemas been updated if the specification changed
• [ ] Has spec version and event versions been updated according to the versioning policy
• [ ] Meets the CDEvents contributor standards

[e-backmark-ericsson]

See also #215

[xibz]

This does get rid of cancel. Should that be a value that we still need, though?

[olensmar]

@xibz sorry for the later reply - change is fine by me!

[xibz]

@xbcsmith can you DCO sign this please, and we can merge it