Prefixed archiveName with 'ehcache'

now we're getting :
```
./107/build/libs/ehcache3-107-3.0.0-SNAPSHOT.jar
./api/build/libs/ehcache3-api-3.0.0-SNAPSHOT.jar
./core/build/libs/ehcache3-core-3.0.0-SNAPSHOT.jar
./impl/build/libs/ehcache3-impl-3.0.0-SNAPSHOT.jar
```