Add primary subAttribute to addresses multi-value attribute of User schema

[brianpeiris]

Similar to #17 and #18, this PR adds the missing "primary" sub-attribute to the "addresses" attribute on the User schema.
The "primary" attribute is one of the default sub-attributes for multi-valued attributes as defined in RFC 7643, section 2.4, with an example of this in demonstrated in section 8.2.

Okta includes this "primary" sub-attribute on addresses by default.

[sleelin]

Thanks @brianpeiris, just in the nick of time, as I was just preparing to release v1.1.0!

This is another example of just how inconsistent the SCIM specification RFC is! When setting out the default attributes in RFC7643§2.4, there's no real explanation of what is meant by "if not otherwise defined". It's clear that these should be used for all other complex multi-value User attributes set out in RFC7643§4.1.2, but the addresses attribute is otherwise defined in this section? This leaves open my initial interpretation that the default attributes are intentionally missing from the addresses attribute (as explained in PR #9), supported by the User resource schema representation in section 8.7.1, which does not include any of the default multi-value attributes.

As you pointed out though, this is contradicted by the addresses value of the Full User JSON representation in section 8.2, and of the Enterprise User Extension JSON representation in section 8.3, which do include the primary attribute in the first listed address.

I still hold my original view from PR #9 that proper conformance to the specification means the primary attribute should not be included as a sub-attribute of addresses. As Okta doesn't agree though, it may be prudent at this time to include it out of the box in the next release, as being "in the spirit" of the specification.

Thanks,
Sam

[brianpeiris]

Thanks for the quick merge. Glad it got in for the next release. I agree the spec is not very clear, and obviously Okta interpreted it in their own way. Seems sensible to follow the spirit of the spec, as you've mentioned.