publish 1.0.6 for Scala 2.12

[SethTisue]

1.0.5 got published for 2.12 as part of the 2.12 release process, but 1.0.6 didn't

[SethTisue]

I did it manually just now by borrowing and running @lrytz's script https://github.com/scala/scala-partest/blob/master/admin/releaseManual.sh

sigh. it would be nice to have a better solution for this in the future, as discussed at scala/scala-partest#37

[SethTisue]

artifacts made it to Maven Central

[SethTisue]

1.0.6 was bundled with Scala 2.12.1, which came out today