Add package.json for UPM

package.json

@@ -0,0 +1,12 @@
+{
+  "name": "com.udexreal.handdriver",
+  "displayName": "Hand Driver",
+  "version": "2.1.8",
+  "unity": "2021.3",
+  "description": "Hand Driver",
+  "author": {
+    "name": "Udexreal"
+  },
+  "dependencies": {
+  }
+}