fix rseed() param validation

Author: luizbills

package.json

@@ -1,6 +1,6 @@
 {
     "name": "litecanvas",
-    "version": "0.98.3",
+    "version": "0.98.4",
     "description": "Lightweight HTML5 canvas 2D game engine suitable for small projects and creative coding. Inspired by PICO-8 and p5.js/Processing.",
     "license": "MIT",
     "author": "Luiz Bills <luizbills@pm.me>",

src/index.js

@@ -351,10 +351,9 @@ export default function litecanvas(settings = {}) {
          */
         rseed(value) {
             DEV: assert(
-                null == value || (isNumber(value) && value >= 0),
-                '[litecanvas] rseed() 1st param must be a positive number or zero'
+                isNumber(value) && value >= 0,
+                '[litecanvas] rseed() 1st param must be a positive integer or zero'
             )
-
             _rngSeed = ~~value
         },