support/scripts/gitlab-ci.yml.in: use get-developers -v in check-DEVELOPERS

Now that we have a working mechanism to validate the DEVELOPERS file
with the get-developers -v option, let's use it.

This brings back proper validation of the DEVELOPERS file, as
get-developers without argument no longer did any validation following
commit 45aabcddc5 utils/get-developers: really make it callable from
elsewhere than the toplevel directory".

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

support/misc/gitlab-ci.yml.in

@@ -3,11 +3,8 @@
         - python3 -m pytest -v utils/checkpackagelib/
 
 .check-DEVELOPERS_base:
-    # get-developers should print just "No action specified"; if it prints
-    # anything else, it's a parse error.
-    # The initial ! is removed by YAML so we need to quote it.
     script:
-        - "! utils/get-developers | grep -v 'No action specified'"
+        - utils/get-developers -v
 
 .check-flake8_base:
     script: