Version hashes from jitpack are detected as main classes

[ctrueden]

With the shell script version of jgo:

$ jgo -U -v sc.iview:sciview:a7ca388
[INFO] Artifact:
[INFO] - groupId    = sc.iview
[INFO] - artifactId = sciview
[INFO] - version    = RELEASE
[INFO] - classifier = <none>
[INFO] Workspace = /Users/curtis/.jgo/sc.iview/sciview/a7ca388
++ mvn -B -U -f /Users/curtis/.jgo/sc.iview/sciview/a7ca388/pom.xml dependency:resolve
+ ln -s /Users/curtis/.m2/repository/com/miglayout/miglayout/3.7.4/miglayout-3.7.4-swing.jar /Users/curtis/.jgo/sc.iview/sciview/a7ca388
... lots more linking ...
+ java -cp '/Users/curtis/.jgo/sc.iview/sciview/a7ca388/*' a7ca388
Error: Could not find or load main class a7ca388

The version is erroneously detected as RELEASE, with main class a7ca388. This is probably because when given an x:y:z triple, we need to detect whether z is a main class or a version number. That heuristic needs to be tweaked to work properly with jitpack version hashes.