README.md: Adjust NodeJS version note for v6 or v7

README.md

@@ -36,7 +36,7 @@ A few suggestions to help you get a good looking site quickly:
 See the source code and structure of [picturingjordan.com](https://github.com/alanorth/picturingjordan.com) to get more ideas.
 
 ## Building (For Developers)
-This theme uses the [Bootstrap](https://getbootstrap.com/) framework. A static version of this is already included, but if you want to bump the version, tweak the style, etc, you'll need to rebuild the assets. Make sure you have NodeJS >= v6 installed, and then run the following from inside the theme's directory:
+This theme uses the [Bootstrap](https://getbootstrap.com/) framework. A static version of this is already included, but if you want to bump the version, tweak the style, etc, you'll need to rebuild the assets. Make sure you have NodeJS v6 or v7 installed, and then run the following from inside the theme's directory:
 
 ```console
 $ npm install