Update README. Remove dev preview warning

Author: charlespwd

README.md

@@ -23,8 +23,6 @@
 
 [Prettier](https://prettier.io) is an opinionated code formatter. It enforces a consistent style by parsing your code and re-printing it with its own rules that take the maximum line length into account, wrapping code when necessary.
 
-**This is the developer preview** of the Liquid/HTML prettier plugin.
-
 ![demo](https://github.com/Shopify/prettier-plugin-liquid/blob/main/docs/demo.gif?raw=true)
 
 ## Can this be used in production?