Force update of repo2docker Docker image

[pierrepo]

With the current situation:

plasma/ansible/tljh.yml

Lines 46 to 51 in d7d6703

	# Pull the repo2docker image to build user images
	- name: Pull the repo2docker Docker image
	docker_image:
	name: quay.io/jupyterhub/repo2docker
	tag: main
	source: pull

The Docker image of repo2docker is never updated. According to Ansible documentation, we should add the parameter:

force_source: yes

to update repo2docker to the newest version.

@jtpio what do you think?

[jtpio]

That would make sense yes. Although it's also useful to be able to rollback to a previous version in case the new version breaks building environments (although unlikely).

Another approach would be to use an explicit version, as repo2docker is now using CalVer for versioning: