gitlab-ci: Use compiler warning level 2 in Meson build

6 jobs for warnlevel in 12 minutes and 11 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #80787
build autotools

00:00:54

passed #80788
build meson

00:05:49

 
  Test
passed #80790
distcheck autotools

00:01:57

passed #80792
doc-and-install meson

00:06:21

passed #80789
test autotools

00:01:29

failed #80791
allowed to fail
test meson

00:02:04

 
Name Stage Failure
failed
test meson Test
--- command ---
BUILT_WITH_MESON='1' /builds/xhaakon/libnice/build/tests/nice-test-new-dribble
-------

Full log written to /builds/xhaakon/libnice/build/meson-logs/testlog.txt
Uploading artifacts...
build/meson-logs/: found 4 matching files
Uploading artifacts to coordinator... ok
id=80791 responseStatus=201 Created token=-FcFyz6Y
ERROR: Job failed: exit code 1