Users contributing to our code should get a welcome message. See some examples:
- Cannot build Repo2Docker image: collision of dependency `six` · Issue #1039 · jupyterhub/repo2docker · GitHub
- replace mamba & conda with micromamba by madhur-tandon · Pull Request #1038 · jupyterhub/repo2docker · GitHub
We need a user story for our Sprint 0 stories for this.