gitlab-ci: Use templates from wayland/ci-templates
These are already used by xserver, Mesa and some other projects.
Current Debian testing brings e.g. GCC 8.3.0 and clang 7.0.1.
These are already used by xserver, Mesa and some other projects.
Current Debian testing brings e.g. GCC 8.3.0 and clang 7.0.1.