Update regulatory docs links for South Africa

[jpmeijers]

Summary

The radio regulations link was dead. Replaced with a more official one. Added a link to the amendment document from December 2021.

Screenshots

...

Changes

• ...
• ...

Notes for Reviewers

...

Checklist

• [ ] Scope: The referenced issue is addressed, there are no unrelated changes.
• [ ] Run Locally: Verified that the docs build using make server, posted screenshots, verified external links.
• [ ] Style Guidelines: Documentation obeys style guidelines in CONTRIBUTING.
• [ ] Commits: Commit messages follow guidelines in CONTRIBUTING, there are no fixup commits left.

[jpmeijers]

@benolayinka could you please review and merge this PR?

[jpmeijers]

Finally! Thanks @nejraselimovic

[nejraselimovic]

Finally! Thanks @nejraselimovic

Sorry for the delay @jpmeijers. I wasn't aware of this PR, as this repo somehow didn't have codeowners set.