v1.2.0

Adding a Docker container to be able to run the oneshot ci runner

This change exports the
`docker.pkg.github.com/omegaup/quark/omegaup-runner-ci` container.

Sample usage:

```shell
$ docker run -it --rm --volume "${PWD}:/src/" \
  docker.pkg.github.com/omegaup/quark/omegaup-runner-ci \
  -oneshot=ci \
  -input=mycoolproblem/ \
  -results=results/
```

This is a #minor change.