build(deps): bump jupyter-server from 2.0.6 to 2.7.2#838

dependabot[bot] wants to merge 2 commits intomasterjupyter-incubator/sparkmagic:masterfrom

dependabot/pip/jupyter-server-2.7.2jupyter-incubator/sparkmagic:dependabot/pip/jupyter-server-2.7.2Copy head branch name to clipboard