Upgrading bootstrap-vue in gitlab-ui

This post details how GitLab CI was leveraged to publish unreleased NPM package versions as CI artifacts, enabling iterative testing of the bootstrap-vue upgrade within the main GitLab application. It also covers the technical challenges and solutions for migrating Karma tests to Jest and using `attachToDocument` and mocking to handle component dependencies during testing, specifically addressing issues with the refactored tooltip and popover components in bootstrap-vue 2.0.