Cannot update expired GPG key with extended expiry date

My GPG key expired, so I've extended the expiry date for another five years. I cannot find any way to import this updated key into keybase.

The website now insists that I must use the CLI tool to add a key (none of the old curl + gpg tricks seem to be supported).

* Using `keybase pgp update` results in `▶ ERROR updated key isn't an active key (code 902)`
* Using `keybase pgp select --multi` results in `▶ ERROR updated key isn't an active key (code 902)`
* Using `gpg --export-secret-key -a 0xB1A5BC141F6BEEE5 | keybase pgp import` results in `▶ INFO Key 010151f54bc90f1d8d62a1ca0b1a1b30312efa94580ade406c9d8b4770a0762a83be0a already exists. Only importing the private key.`

While the last one looks like it might have done something, the key is still not visible on my profile: https://keybase.io/jonty

I have no idea what else to try!

Start by reproducing the failure with `keybase pgp update`, `keybase pgp select --multi`, and the `gpg --export-secret-key ... | keybase pgp import` command. Check how an expired key and its extended expiry are handled, then verify that the updated key becomes visible on the reported Keybase profile.

Written by the indexing model from the issue text.