bump api to 1.14 & update docs

Docker-DCO-1.1-Signed-off-by: Adrien Folie <folie.adrien@gmail.com> (github: folieadrien)
proper rebase

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
Merge pull request #6985 from vieux/fix_api_1.14

bump api to 1.14 & update docs