Bump version to 19.03.6.rc1

[arkodg]

No description provided.

[arkodg]

PTAL @thaJeztah @tonistiigi @tiborvass

[thaJeztah]

Note: a bunch of PR's were just merged into docker/engine, so some updates are needed to the changelog (also; we need to make sure the update components script is run before we merge/tag/do anything)

One more PR is pending CI to run; docker-archive/engine#454

bad links

[mrueg]

FYI there was a new runc release fixing a CVE: https://github.com/opencontainers/runc/releases/tag/v1.0.0-rc10

[thaJeztah]

IIUC, the runc CVE doesn't directly affect docker (due to it setting up mounts differently), but will be included in an update of the containerd.io package (which currently contains the runc binary). A new release of containerd should be tagged upstream with the updated runc version

[dims]

@thaJeztah looking at the tgz files in https://download.docker.com/linux/static/stable/x86_64/ (say 19.03.5) there seems to be a copy of runc in there as well. would that reflect the version number of the runc from github.com/containerd/containerd/vendor.conf ?

(So we would have to bump containerd version here in this repo in the components/engine/vendor.conf after that?)