Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>..

Mark Cluster Autoscaler as GA (1.0.0)

This is basically the same version as 0.7.0(-beta2). However to reduce confusion among users we decided to name the first GA version of CA as 1.0.0.

```release-note
Cluster Autoscaler 1.0.0
```