maint: added minmaxslider package

Assets/SimpleMinMaxSlider/Scripts/MinMaxSliderExample.cs

@@ -0,0 +1,16 @@
+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+using GD.MinMaxSlider;
+
+public class MinMaxSliderExample : MonoBehaviour
+{
+
+    public string info = "Hover over a slider to see a tooltip";
+
+    [MinMaxSlider(0,10)]
+    public Vector2 floatRange = new Vector2(2,8);
+    [MinMaxSlider(0,10)]
+    public Vector2Int intRange = new Vector2Int(1,5);
+
+}