ngrok-agent needs to be updated

[Vampire]

As tmate.io was discontinued and thus https://github.com/mxschmitt/action-tmate is not useable out-of-the box anymore I was searching for a cross-platform replacement option.

I tried to test your action, but it fails with

t=2025-08-14T14:59:26+0000 lvl=eror msg="failed to auth" obj=tunnels.session err="Your ngrok-agent version \"2.3.41\" is too old. The minimum supported agent version for your account is \"3.7.0\". Please update to a newer version with `ngrok update`, by downloading from https://ngrok.com/download, or by updating your SDK version. Paid accounts are currently excluded from minimum agent version requirements. To begin handling traffic immediately without updating your agent, upgrade to a paid plan: [https://dashboard.ngrok.com/billing/subscription.\r\n\r\nERR_NGROK_121\r\n](https://dashboard.ngrok.com/billing/subscription./r/n/r/nERR_NGROK_121/r/n)"

unless one switches to a paid plan, so please update the ngrok-agent or maybe even incorporate an auto-update if possible