[vala] (14 commits) Non-fast-forward update to branch wip/ci

[Rico Tzschichholz <ricotz src gnome org>]

The branch 'wip/ci' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  44a3dd9... coverage: Build gidl-bindings
  c7585ef... ci: Add .gitlab-ci.yml
  024f55b... ci: Add ubuntu:16.04 run with gcc
  67860de... ci: Add ubuntu:18.04 run with gcc
  b2e7f15... ci: Add fedora:latest run with clang
  ff226e1... ci: Add archlinux/base:latest run with gcc
  6b2e99d... ci: Always deploy

Commits added to the branch:

  2661221... vala: Respect --abi-stability in Class/Interface.accept_chi (*)
  d79401a... vala: Accept interface as inner type for object-type symbol (*)
  b1d2580... glib-2.0: Add binding for "warning_once()" since 2.64 (*)
  377dd29... gstreamer: Update from 1.17.0+ git master (*)
  4ad6246... webkit2gtk-4.0: Update to 2.27.1 (*)
  555a434... vapi: Update GIR-based bindings (*)
  0943223... girwriter: Restore behaviour for delegate-types (*)
  0364eaf... coverage: Build gidl-bindings
  ade7f76... ci: Add .gitlab-ci.yml
  4285182... ci: Add ubuntu:16.04 run with gcc
  b8864b8... ci: Add ubuntu:18.04 run with gcc
  301ae48... ci: Add fedora:latest run with clang
  d78581e... ci: Add archlinux/base:latest run with gcc
  39112dc... ci: Always deploy

(*) This commit already existed in another branch; no separate mail sent