Notify key custodians of signing dates
Description
In advance, notify all key holders with the dates for next signing ceremony, and provide a brief list of the expected changes.
We should also switch out a key custodian, there were talks of doing this last time.
Done https://sigstore.slack.com/archives/C03E4HP6RCK/p1749021576785409
@haydentherapper do we know if there are any candidates? I know that @bobcallaway talked with someone a while back.
Yes, Lance Ball from RedHat, to replace either Joshua or anyone else who wants to switch out. Let's do that switch this cycle, and we should plan to swap out someone else next cycle too.