docs: Fix external link to semantic validations
docs: Fix external link to semantic validations

Update the external link to the semantic validations because the current
one doesn't exist anymore

Signed-off-by: Ivan Fraixedes <a15f8b81a160b4eebe5c84e9e3b65c87b9b2f18e@fraixed.es>

ThalesIgnite/go-swagger,ThalesIgnite/go-swagger,go-swagger/go-swagger,go-swagger/go-swagger