[MNG-6571] forgot to put new instance in cache

maven-artifact/src/main/java/org/apache/maven/artifact/versioning/VersionRange.java

@@ -241,6 +241,7 @@ public class VersionRange
         {
             List<Restriction> restrictions = Collections.emptyList();
             cached = new VersionRange( new DefaultArtifactVersion( version ), restrictions );
+            CACHE.put( version, cached );
         }
         return cached;
     }