Update README.md with "maintained by Plotly" badge

Author: gvwilson

README.md

@@ -16,6 +16,13 @@ Plotly.js can be used to produce dozens of chart types and visualizations, inclu
 
 [Contact us](https://plotly.com/products/consulting-and-oem/) for Plotly.js consulting, dashboard development, application integration, and feature additions.
 
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+  <a href="https://dash.plotly.com/project-maintenance">
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 ## Table of contents
 
 * [Load as a node module](#load-as-a-node-module)