docs: update recommended node version (#1053)

Author: naokie

src/guide/ssr/getting-started.md

@@ -14,7 +14,7 @@ yarn add @vue/server-renderer
 
 #### Notes
 
-- It's recommended to use Node.js version 10+.
+- It's recommended to use Node.js version 12+.
 - `@vue/server-renderer` and `vue` must have matching versions.
 - `@vue/server-renderer` relies on some Node.js native modules and therefore can only be used in Node.js. We may provide a simpler build that can be run in other JavaScript runtimes in the future.