This commit adds a new `LoadDockerAuthConfigs` function, which loads all
registry auths that are configured on the host and sends them with the build
command to the docker daemon.
This is needed in case act builds a docker action and the images referenced in
that docker action are located on private registries or otherwise require
authentication (e.g. to get a higher rate limit).
The code is adapted from how the docker cli works:
257ff41304/cli/command/image/build.go (L323-L332)
Co-authored-by: Markus Wolf <mail@markus-wolf.de>
Co-authored-by: Markus Wolf <mail@markus-wolf.de>
3f3b25ae84