Deprecation warning (promisify) when upgrading to Node v21.6.0

Checklist

[X] The issue can be reproduced in the express-openid-connect sample app (or N/A).
[X] I have looked into the Readme, Examples, and FAQ and have not found a suitable solution or answer.
[X] I have looked into the API documentation and have not found a suitable solution or answer.
[X] I have searched the issues and have not found a suitable solution or answer.
[X] I have searched the Auth0 Community forums and have not found a suitable solution or answer.
[X] I agree to the terms within the Auth0 Code of Conduct.

Description

Hello 👋

We recently upgraded our Node service to v21.6.0 and we start to see some deprecation warning:

[DEP0174] DeprecationWarning: Calling promisify on a function that returns a Promise is likely a mistake.

With --trace-deprecation argument, we can see those warnings come from the lib:

(node:45354) [DEP0174] DeprecationWarning: Calling promisify on a function that returns a Promise is likely a mistake.
    at node:internal/util:431:17
    at new Promise (<anonymous>)
    at RedisStore.get (node:internal/util:416:12)
    at CustomStore.get (/REDACTED/REDACTED/REDACTED/REDACTED/apps/api-server/node_modules/.pnpm/express-openid-connect@2.17.1_express@4.18.2/node_modules/express-openid-connect/lib/appSession.js:203:19)
    at /REDACTED/REDACTED/REDACTED/REDACTED/apps/api-server/node_modules/.pnpm/express-openid-connect@2.17.1_express@4.18.2/node_modules/express-openid-connect/lib/appSession.js:325:46
    at /REDACTED/REDACTED/REDACTED/REDACTED/apps/api-server/node_modules/.pnpm/dd-trace@4.23.0/node_modules/dd-trace/packages/datadog-instrumentations/src/router.js:22:57
    at /REDACTED/REDACTED/REDACTED/REDACTED/apps/api-server/node_modules/.pnpm/dd-trace@4.23.0/node_modules/dd-trace/packages/datadog-shimmer/src/shimmer.js:26:21
    at Layer.handle [as handle_request] (/REDACTED/REDACTED/REDACTED/REDACTED/apps/api-server/node_modules/.pnpm/express@4.18.2/node_modules/express/lib/router/layer.js:95:5)
    at trim_prefix (/REDACTED/REDACTED/REDACTED/REDACTED/apps/api-server/node_modules/.pnpm/express@4.18.2/node_modules/express/lib/router/index.js:328:13)
    at /REDACTED/REDACTED/REDACTED/REDACTED/apps/api-server/node_modules/.pnpm/express@4.18.2/node_modules/express/lib/router/index.js:286:9
    at Function.process_params (/REDACTED/REDACTED/REDACTED/REDACTED/apps/api-server/node_modules/.pnpm/express@4.18.2/node_modules/express/lib/router/index.js:346:12)
    at Function.process_params (/REDACTED/REDACTED/REDACTED/REDACTED/apps/api-server/node_modules/.pnpm/dd-trace@4.23.0/node_modules/dd-trace/packages/datadog-instrumentations/src/express.js:70:23)
    at next (/REDACTED/REDACTED/REDACTED/REDACTED/apps/api-server/node_modules/.pnpm/express@4.18.2/node_modules/express/lib/router/index.js:280:10)
    at Function.handle (/REDACTED/REDACTED/REDACTED/REDACTED/apps/api-server/node_modules/.pnpm/express@4.18.2/node_modules/express/lib/router/index.js:175:3)
    at router (/REDACTED/REDACTED/REDACTED/REDACTED/apps/api-server/node_modules/.pnpm/express@4.18.2/node_modules/express/lib/router/index.js:47:12)
    at /REDACTED/REDACTED/REDACTED/REDACTED/apps/api-server/dist/main.js:587:14

This comes from this code https://github.com/auth0/express-openid-connect/blob/8ade66846a1f041591e267d2296b02df2604f1f4/lib/appSession.js#L190

Reproduction

Tested in the express-opend-id-connect sample app:

const dotenv = require("dotenv");
const express = require("express");
const http = require("http");
const logger = require("morgan");
const path = require("path");
const router = require("./routes/index");
const { auth } = require("express-openid-connect");

// Redis store
const { createClient } = require("redis");
const RedisStore = require("connect-redis").default;
let redisClient = createClient();
redisClient.connect().catch(console.error);

dotenv.load();

const app = express();

app.set("views", path.join(__dirname, "views"));
app.set("view engine", "ejs");

app.use(logger("dev"));
app.use(express.static(path.join(__dirname, "public")));
app.use(express.json());

const config = {
  authRequired: false,
  auth0Logout: true,
  session: {
    store: new RedisStore({ client: redisClient }),
  },
};

(...)

Additional context

No response

express-openid-connect version

2.17.1

Express version

4.18.2

Node.js version

21.6.0

auth0 / express-openid-connect

Deprecation warning (promisify) when upgrading to Node v21.6.0 #571