[ci] collect image for other images

[lalo]

solves #1164

[lalo]

@chwarr not sure which python format tool you used before, tried black but it's messing too many things. BTW, haven't executed this code

[chwarr]

I don't think I used a Python formatting tool. I used pylint for linting and Mypy for static typing. I probably used Emacs' python-mode for formatting. The indentation style where arguments are indented to the opening parenthesis looks like what python-mode would do:

    parser.add_argument('root_filters',
                        nargs='+',
                        type=semi_list,
                        help="""semi-colon seperated list of arguments for one invocation of `git
                        rev-parse`. The commits in the union of these
                        rev-parse invocations are used to find container images
                        that are referenced by source code. Ex:
                        '--remotes=origin;--since=2~weeks~ago' or '--tags;-n;1'""")