Update readme: mention next-version

README.md

@@ -4,6 +4,8 @@ This is a template project for creating [OPENRNDR](https://openrndr.org/) progra
 For making a standard Kotlin/JVM-based application,
 see [openrndr-template](https://github.com/openrndr/openrndr-template).
 
+## Developing
+
 To get started developing, run 
 
 ```bash
@@ -14,6 +16,8 @@ This will start a local development server with hot-reloading.
 
 Any changes you make in `/src/main/kotlin` will be reflected in the browser.
 
+## Exporting
+
 When the project is ready to be shared, one can export a minimized executable by running
 
 ```bash
@@ -22,3 +26,9 @@ When the project is ready to be shared, one can export a minimized executable by
 
 This will place an `index.html` file and the `openrndr-program.js`
 under the `build/dist/js/productionExecutable/` folder.
+
+## next-version branch
+
+Note that there is a `next-version` branch which may offer better performance or
+new features.
+