message: fix(readme): link target and title
diff: @@ -172,7 +172,7 @@ Understanding the Superset Points of View
  - [Building a Database Connector for Superset](https://preset.io/events/2021-02-16-building-a-database-connector-for-superset/)
  - Visualizations
  - - [Building Custom Viz Plugins](https://superset.apache.org/docs/installation/building-custom-viz-plugins)
  + - [Creating Viz Plugins](https://superset.apache.org/docs/contributing/creating-viz-plugins/)
  - [Managing and Deploying Custom Viz Plugins](https://medium.com/nmc-techblog/apache-superset-manage-custom-viz-plugins-in-production-9fde1a708e55)
  - [Why Apache Superset is Betting on Apache ECharts](https://preset.io/blog/2021-4-1-why-echarts/)
  