plainbox: post-release bump to 0.18.dev

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
plainbox:docs: update changelog

This patch updates the changelog all the way up to the 0.18 dev version.
We've kind of forgot to do that periodically before.

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
providers:ubuntu-touch: bump version to 1.1

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
"automatic merge of lp:~zkrynicki/checkbox/plainbox-0.17/ by tarmac [r=zkrynicki][bug=][author=zkrynicki]"
"automatic merge of lp:~zkrynicki/checkbox/touch-provider-1.0/ by tarmac [r=kissiel][bug=][author=zkrynicki]"