Parallelize unit tests

mentioned in merge request gitlab-org/cli!1982 (closed)

mentioned in merge request gitlab-org/terraform-provider-gitlab!2374 (merged)

mentioned in merge request gitlab-org/release-tools!3996 (merged)

mentioned in merge request gitlab-org/terraform-provider-gitlab!2376 (closed)

mentioned in merge request gitlab-com/gl-infra/oncall-robot-assistant!79 (merged)

mentioned in merge request gitlab-com/gl-infra/platform/runway/runwayctl!879 (merged)

mentioned in merge request gitlab-com/gl-infra/autolabels!22 (merged)

mentioned in merge request gitlab-com/gl-infra/ringctl!248 (merged)

mentioned in merge request fforster/epic-update!8 (merged)

mentioned in merge request ydkn/gitlab-runner-cleanup!36 (closed)

mentioned in merge request gitlab-org/container-registry!2154 (merged)

mentioned in merge request sue445/tanuki_reminder!233 (merged)

mentioned in merge request sue445/create-merge-request!116 (merged)

mentioned in merge request gitlab-com/content-sites/handbook-tools/hugolint!123 (merged)

mentioned in merge request !2235 (merged)

mentioned in merge request !2265 (merged)