napi: temporarily disable v6 (see issue #1444)

Author: kewde

package.json

@@ -14,8 +14,7 @@
     "remote_path": "./{name}/v{version}/{toolset}/",
     "package_name": "napi-v{napi_build_version}-{platform}-{arch}.tar.gz",
     "napi_versions": [
-      3,
-      6
+      3
     ]
   },
   "contributors": [