Bump version 0.2.1 -> 0.2.2

Now that we've added the `ignores` configuration option, we want to cut
a new version of the gem.

Change-Id: I97e9ccb53e474e166ca5944d6864d2edd13354e0
Reviewed-on: http://gerrit.causes.com/40206
Tested-by: Henric Trotzig <henric.trotzig@brigade.com>
Reviewed-by: Henric Trotzig <henric.trotzig@brigade.com>