Co-authored-by: Rhys Arkins <rhys@arkins.net>

Co-authored-by: Renovate Bot <bot@renovateapp.com>
Co-authored-by: Jamie Magee <jamie.magee@gmail.com>
Co-authored-by: Michael Kriese <michael.kriese@visualon.de>
Co-authored-by: Jamie Magee <JamieMagee@users.noreply.github.com>

* chore(deps): update dependency prettier to v2

* Run prettier-fix

Co-authored-by: Renovate Bot <bot@renovateapp.com>
Co-authored-by: Jamie Magee <jamie.magee@gmail.com>

Renovate did not recognize images where "image" was the first key in the YAML mapping inside the YAMl container list/array

Add support for renovating Docker images in Kubernetes manifests

"docker" in config now refers to the Docker "language", which is the parent of dockerfile, docker-compose and circleci managers.

Removes custom Docker lookup code and instead integrates it with the generic lookup routine used by other package managers. Logic for digest support was added but is used by Docker-only for now.

Closes #2081, Closes #2276

Initially docker versioning is just a node semver wrapper, but it will later be expanded with custom support for docker-specific version tags.

Manually finds and massages node updates in Docker, Docker Compose and Circle CI so that they should take on the same “renovate/node-8.x” style branch naming. The goal is to unify all node updates into a single branch.

e.g. ${TAG}

Adds support for renovating Docker Compose files (e.g. `docker-compose.yml`). Functionality is essentially the same as the existing `Dockerfile` capabilities, so config for `docker` is shared with `docker-compose` but may also be overridden.

Merging as disabled by default - will wait for some opt-in testing before turning it on by default.

Closes #832