Specify how to upgrade the Webhook TLS once it is expired in the Documentation

[xavidop]

After one year of running telepresence on our cluster, the injector webhook TLS certificate stored in a secret expired on our cluster.

To solve this, I had to uninstall and install the Helm chart to renew it. With the latest version of telepresence CLI, you can renew it by running telepresence helm install --upgrade.

It would be fantastic if you can specify how to renew that certificate on the documentation.

Also as an automated solution, would be fantastic if you can create a cronjob that automatically renews that certificate before it expires.

Also, for just renewing this certificate, maybe would be clearer in terms of UX of the CLI to have just a command to do that: telepresence cert renew. Or something like that