core: connection: use subscription_id, add resume support

packages/hydrooj/package.json

@@ -60,7 +60,7 @@
         "@types/fs-extra": "^11.0.4",
         "@types/js-yaml": "^4.0.9",
         "@types/koa-static-cache": "^5.1.4",
-        "@types/lodash": "^4.17.17",
+        "@types/lodash": "^4.17.18",
         "@types/mime-types": "^2.1.4",
         "@types/mongodb-uri": "^0.9.4",
         "@types/nodemailer": "^6.4.17",