[UIMA-6108] switch version to 3.1.0-SNAPSHOT
[UIMA-6108] switch version to 3.1.0-SNAPSHOT

git-svn-id: d56ff9e7d7ea0b208561738885f328c1a8397aa6@1864549 13f79535-47bb-0310-9956-ffa450edef68

apache/uima-uimaj,apache/uima-uimaj,apache/uima-uimaj,apache/uima-uimaj,apache/uima-uimaj