Describe the feature or problem you’d like to solve

In case we aren't using the latest CLI version, every time we run the CLI locally or inside a CI job, we get a message like the next:

A new release of gh is available: 0.10.1 → v1.0.0
https://github.com/cli/cli/releases/tag/v1.0.0

This message is printed to the stderr (which generates unnecessary noise in CI jobs) and also it causes a small delay due to the external request, so we would like to be able to disable this check in some way.

Proposed solution

A switch to enable/disable the new release check. For example, by using an environment variable GHCLI_CHECK_UPDATES=<true|false> and/or a new boolean setting check_updates for the gh config command.