package.json: Allow any version of node that supports the syntax

There's no reason to exclude newer versions of Node in the engines
field, and it causes errors for users of the package when installing.
Anything from Node 8 on can run this code.

Author: mjesuele

package.json

@@ -83,6 +83,6 @@
 		"react-dom": "^15.3.0 || ^16.0.0"
 	},
 	"engines": {
-		"node": "^12 || ^10 || ^8"
+		"node": ">= 8"
 	}
 }