README.md: Fixed incorrect Docker version references
I happened to see that the information was outdated.
@@ -21,7 +21,7 @@ It is used it in many critical production systems at Spotify.
## Version compatibility
docker-client is built and tested against the six most recent minor releases of Docker.
-Right now these are 1.9.1 - 17.04.0-ce (specifically the ones [here][1]).
+Right now these are 1.12.6 - 17.09.0-ce (specifically the ones [here][1]).
We upload the artifact tested on Docker 1.13.1.
See [Docker docs on the mapping between Docker version and API version][3].
