apt update yields GPG error because Github CLI's apt key expired

[hello-binit]

See cli/cli#9569 for details / the fix. The errors will look like:

$ sudo apt update
[...]
Err:3 https://cli.github.com/packages stable InRelease                                                                               
  The following signatures were invalid: EXPKEYSIG 23F3D4EA75716059 GitHub CLI <[email protected]>
Fetched 264 kB in 2s (129 kB/s)
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://cli.github.com/packages stable InRelease: The following signatures were invalid: EXPKEYSIG 23F3D4EA75716059 GitHub CLI <[email protected]>
W: Failed to fetch https://cli.github.com/packages/dists/stable/InRelease  The following signatures were invalid: EXPKEYSIG 23F3D4EA75716059 GitHub CLI <[email protected]>
W: Some index files failed to download. They have been ignored, or old ones used instead.

TODO:

• Document the error / reference the fix above in the troubleshooting section.
• Post on the forum to let users know. Here's the forum post from last time this happened (OpenRobotics' ROS Apt key had expired).