Image automation controller

This controller automates updates to YAML when new container images
are available.
Its sibling,
image-reflector-controller,
scans container image repositories and reflects the metadata in
Kubernetes resources. This controller reacts to that image metadata by
updating YAML files in a git repository, and committing the changes.
How to install it
Please see the installation and use
guide.
How to work on it
The shared library libgit2
needs to be installed to test or build
locally. The version required corresponds to the version of git2go
(which are Go bindings for libgit2), according to this
table.
See
https://github.com/fluxcd/source-controller/blob/main/DEVELOPMENT.md#installing-required-dependencies
for instructions on how to install libgit2
.