fix: As a user I would like that the default package repo use in the gitlab CI be in sync with the rocker/verse version

[ALanguillaume]

Problem

Currently there is a mismatch between the default arguments of use_gitlab_ci().

• image = "rokcer/verse" will cause the runner to start from the latest rocker/verse image which uses ubuntu jammy
  WHEREAS
• repo_name = "https://packagemanager.rstudio.com/all/__linux__/focal/latest" will cause the R packages to be installed as binaries compiled for an earlier version of ubuntu (focal).

This causes some uncanny errors while installing packages with compiled code.

Validation

• When adding a gitlab-ci.yml in a new project the link to posit packagemanager repo corresponds to Ubuntu Jammy which is the version used by the latest rocker/verse image.

Tech

• Change default values for argument repo_name of function use_gitlab_ci() to : https://packagemanager.posit.co/cran/__linux__/jammy/latest