docs: Update subproject patch description
Update Subproject Patch endpoint description in openapi.yaml
Starting on April 8th, The Open Group will require Two Factor Authentication for all GitLab users. For instructions on setting up 2FA, see the Knowledge Article or GitLab Documentation. Note in particular that any HTTPS clones will require the use of a Personal Access Token (rather than a user’s password) once 2FA is enabled.
Update Subproject Patch endpoint description in openapi.yaml