gitlab-ci: Build wlroots

Build it once with and without xwayland so we're sure both work
2 jobs for gitlab-ci in 2 minutes and 50 seconds (queued for 2 seconds)
latest
Status Name Job ID Coverage
  Build
passed build-with-xwayland #165
librem5

00:01:25

passed build-without-xwayland #166
librem5

00:01:24