Fix RCs publishing

Release Dotty 0.7.0

Release Dotty 0.7.0-RC1

Release stable 0.6.0

Release Dotty 0.6.0-RC1

Release Dotty 0.5.0-RC1

Release Dotty 0.4.0-RC1

Merge pull request scala#3078 from allanrenucci/0.3.x

Backport scala#3076

Release 0.2

Merge pull request scala#3002 from dotty-staging/topic/release-0.3.0-RC1

Change build version number for 0.3.0-RC1 release