chore: update to Unity 6000.3.18f1 (#2722)

Author: github-actions[bot]

scripts/unity-versions.json

@@ -12,7 +12,7 @@
     "changeset": "88f89d0d8b31"
   },
   "6000.3": {
-    "version": "6000.3.17f1",
-    "changeset": "cf0352b38e81"
+    "version": "6000.3.18f1",
+    "changeset": "5ebeb53e4c07"
   }
 }