Add proxy server workaround for Contabo Server issue

[vishwamartur]

Related to #1314

Add a proxy server workaround for 'Sign in to confirm you’re not a bot' error on Contabo Server.

• example/proxy.js

  • Update the proxy URL to a working proxy server.
  • Add comments explaining how to configure the proxy server.

• README.md

  • Add a section explaining the proxy server workaround.
  • Include instructions on how to configure the proxy server with an example.

[tempiltin]

this package not working: [nodemon] starting node index.js
C:\Users\User\Desktop\bot\node_modules\ytdl-core\lib\sig.js:20
throw Error('Could not extract functions');
^

Error: Could not extract functions
at C:\Users\User\Desktop\bot\node_modules\ytdl-core\lib\sig.js:20:11
at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
Emitted 'error' event on PassThrough instance at:
at process.processTicksAndRejections (node:internal/process/task_queues:105:5)

Node.js v22.12.0
[nodemon] app crashed - waiting for file changes before starting...