dep-dev: bump docker from 20.10.12 to 20.10.13 in /.gitlab/docker/ci

Can't show this merge request because the source branch dependabot-docker-.gitlab-docker-ci-docker-20.10.13 is missing from project georgekoltsov-multiple-projects-test-4/imported-project-ef029319134ab099. Close this merge request or update the source branch.