Bump echarts from 5.4.3 to 5.5.0#259

dependabot[bot] wants to merge 1 commit intomasteropenwisp/netjsongraph.js:masterfrom

dependabot/npm_and_yarn/echarts-5.5.0openwisp/netjsongraph.js:dependabot/npm_and_yarn/echarts-5.5.0Copy head branch name to clipboard