fix: use utf-8 in package.json

Author: MtMath

Assets/Package/package.json

@@ -1,4 +1,4 @@
-{
+{
   "name": "com.notask.custom-button",
   "displayName": "Custom Button",
   "version": "1.2.1-preview",
@@ -12,8 +12,8 @@
   "keywords": [
     "custom",
     "button",
-    "unity",
-    "preview"
+    "preview",
+    "unity"
   ],
   "samples": [
     {
@@ -23,4 +23,4 @@
     }
   ],
   "preview": true
-}
+}