Update README.md

Change documentation to note that the plugin is now deprecated

Author: jordanpowell88

README.md

@@ -1,3 +1,5 @@
+## Note: This plugin is deprecated and Cypress will not be moving forward with development of the plugin.
+
 # Cypress Browserify Preprocessor [![CircleCI](https://circleci.com/gh/cypress-io/cypress-browserify-preprocessor/tree/master.svg?style=svg)](https://circleci.com/gh/cypress-io/cypress-browserify-preprocessor/tree/master)
 
 Cypress preprocessor for bundling JavaScript via browserify.
@@ -18,8 +20,6 @@ npm install --save-dev @cypress/browserify-preprocessor
 
 ## Usage
 
-### Note: This Plugin only works for Cypress < 9
-
 In your project's [plugins file](https://on.cypress.io/plugins-guide):
 
 ```javascript