Update fp-004-versioning.md summary fix (#2878)

Author: nataled

principles/fp-004-versioning.md

@@ -7,7 +7,7 @@ GO TO: [Recommendations/Requirements](#recommendations-and-requirements) |
 
 ## Summary
 
-The ontology provider has documented procedures for versioning the ontology, and different versions of ontology are marked, stored, and officially released.
+The ontology provider MUST have documented procedures for versioning the ontology, and different versions of ontology MUST be marked, stored, and officially released.
 
 ## Purpose