Tag 1.8.0

Bump versions to 1.8.0-beta.2

Tag 1.8.0-beta.1

Tag 1.7.1 release

Tag 1.8.0-alpha.1

Mark 1.7.0 kops version

Merge commit '8ea648b71' into release-1.7

Merge pull request kubernetes#2880 from justinsb/tag_17_alpha1

Bump dns-controller & kops for 1.7.0-alpha.1

Release 1.6.2

Version 1.6.1