Added CHROME_PATH to readme (#2694)

Author: lifeisfoo

chrome-launcher/README.md

@@ -41,7 +41,8 @@ npm install chrome-launcher
   handleSIGINT: boolean;
 
   // (optional) Explicit path of intended Chrome binary
-  // If the `LIGHTHOUSE_CHROMIUM_PATH` env variable is set, that will be used
+  // If the `CHROME_PATH` env variable is set, that will be used
+  // Usage of `LIGHTHOUSE_CHROMIUM_PATH` env variable is deprecated
   // By default, any detected Chrome Canary or Chrome (stable) will be launched
   chromePath: string;