Bump debug, browser-sync and serve-index in /frontend#12

dependabot[bot] wants to merge 1 commit intomastermikaelengstrom/django-react-polls-example:masterfrom

dependabot/npm_and_yarn/frontend/debug-and-browser-sync-and-serve-index-2.6.9mikaelengstrom/django-react-polls-example:dependabot/npm_and_yarn/frontend/debug-and-browser-sync-and-serve-index-2.6.9Copy head branch name to clipboard