GitLab

* add additional workflow trigger

* [skip ci] fix name of script for PR label processing (#4013)

* trigger CI

* fix workflow in case commit has no associated PR

* [skip CI] test PR for label-checking workflow (#4015)

* [skip CI] fix PR labels processing logic (#4016)

* [skip CI] try fix trigger for unlabeled PR pings (#4017)

* [skip CI] remove quotes around users ping (#4018)

* [skip CI] cleanup PR labeling workflow (#4019)

* [skip CI] fix ping message for unlabeled PRs (#4020)

* cleanup