Simultaneous fetch is now external package.

Signed-off-by: Toha <tohenk@yahoo.com>

package.json

@@ -30,6 +30,7 @@
     "@alex_neo/jest-expect-message": "^1.0.5",
     "@freearhey/core": "^0.3.1",
     "@freearhey/search-js": "^0.1.1",
+    "@ntlab/sfetch": "^1.0.0",
     "@octokit/core": "^4.1.0",
     "@types/cli-progress": "^3.11.3",
     "@types/fs-extra": "^11.0.2",