Release process

#Preparing a release

1. Bump version number (format: x.x.x) in main.go and README.md.
2. make autoneg-manifests, and replace the Google header in deploy/autoneg.yaml
3. Run VERSION=x.x.x make release-push to build the new image and push to github's registry
4. Commit to master
5. Make github release, with version vx.x.x pointing to the master commit
6. Bump version in main.go to x.x.(x+1)-dev
7. Commit to master