Change title of section 4.6.5 from "Project Homepage" to "Project Link"

Current wording

4.6.5 Project Homepage

Permalink

https://standards.internetofproduction.org/pub/okh#project-homepage

Proposal

Change the title of this section to:

4.6.5 Project Link

Motivation

This section refers to the project-link field in the manifest so it would be better for the section title to match the manifest field name.