Bump version to v1.1.0

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
Merge pull request #6818 from vieux/bump_v1.1.0

Bump v1.1.0
Merge remote-tracking branch 'origin/release'

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
Change version to 1.1.0-dev

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
Merge pull request #6838 from vieux/merge_release_v1.1.0

Merge release v1.1.0