Updating .gitlab-ci.yml to fix TESTSET_DIR

Recent commit d4fa60289423 introduced a test to probe for expected
.bib files under TESTSET_DIR. This commit here populates this
directory structure early during the CI script's run in order to
have all necessary files in place when 'cmake' performs its checks.

Also increasing the version number encoded in variable 'QT_DISABLE_DEPRECATED'.