Update compability doc

[sarthyparty]

Proposed changes

Recently NGF supported port in ParentRefs for routes, so this is an update to the compatibility doc.

Checklist

Before sharing this pull request, I completed the following checklist:

• I read the Contributing guidelines
• My branch adheres to the Git conventions
• My content changes adhere to the F5 NGINX Documentation style guide
• If my changes involve potentially sensitive information¹, I have assessed the possible impact
• I have waited to ensure my changes pass tests, and addressed any discovered issues

Footnotes

1. Potentially sensitive information includes personally identify information (PII), authentication credentials, and live URLs. Refer to the style guide for guidance about placeholder content. ↩

[bjee19]

@sarthyparty this PR will need to target the ngf-release-2.2 branch. Main is what shows up on the site, and thus usually relates to the latest version unless specified otherwise. Since 2.1 doesn't support Port and those changes will be in release 2.2, this will need to go into the other branch for now.