Pin objenesis version to be always 2.2

1 job for master in 2 minutes and 34 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Test
failed test #17742

00:02:34

 
Name Stage Failure
failed
test Test
    [junit] Testcase: testIndexingDisappearingTarball took 0.089 sec
[junit] Testcase: testUpdateFileAfterIndexing took 0.057 sec
[junit] Testcase: testExistingRecentExitList took 0.032 sec

BUILD FAILED
/builds/tpo/metrics/collector/src/build/java/base.xml:189: Test org.torproject.metrics.collector.indexer.CreateIndexJsonTest failed

Total time: 16 seconds
ERROR: Job failed: exit code 1