Fixed broken link in upgrade docs CTR
Fixed broken link in upgrade docs CTR

apache/tinkerpop,apache/incubator-tinkerpop,apache/tinkerpop,apache/tinkerpop,apache/tinkerpop,apache/tinkerpop,apache/incubator-tinkerpop,apache/incubator-tinkerpop,apache/tinkerpop,apache/tinkerpop