Bump webpack-dev-server, @angular-devkit/build-angular and ngx-build-plus in /zeppelin-web-angular#4939

dependabot[bot] wants to merge 1 commit intomasterapache/zeppelin:masterfrom

dependabot/npm_and_yarn/zeppelin-web-angular/multi-2a5d951d87apache/zeppelin:dependabot/npm_and_yarn/zeppelin-web-angular/multi-2a5d951d87Copy head branch name to clipboard