docs: @nuxtjs/composition-api is still needed for 2.7+

Author: JonasV

README.md

@@ -26,7 +26,7 @@ To make `vue-echarts` work for _Vue 2_ (<2.7.0), you need to have `@vue/composit
 npm i -D @vue/composition-api
 ```
 
-If you are using _NuxtJS_ on top of _Vue 2_ (<2.7.0), you'll also need `@nuxtjs/composition-api`:
+If you are using _NuxtJS_ on top of _Vue 2_, you'll also need `@nuxtjs/composition-api`:
 
 ```sh
 npm i -D @nuxtjs/composition-api