Stop the support of Ubuntu 18.04 in doc and CI.
Summary
Ubuntu 22.04 is coming, and known users are working with Ubuntu 20.04
Motivation
Save energy during CI pipelines and avoid the need to deal with 18.04 specifics.
Proposal
Remove documentation and CI tasks related to Ubuntu 18.04 before switcher 3 release.
Impact on already existing code
None
Roadmap
- Remove 18.04 information in documentation
- Remove CI task related to 18,04
More details
None