Merge #861: Final update release key expiration date

ca7a649 Final update release key expiration date (laanwj)

Pull request description:

  Change the expiration to 2024. The key is no longer being used for new releases, but letting it expire now would be inconvenient because there may still be another 0.21.x release, and, people may still want to verify older releases. I've also pushed this key to the `keys.openpgp.org` keyserver.

  This should be enough for all releases signed with it to be EOL. After that, it can be removed from the site completely.

ACKs for top commit:
  gruve-p:
    ACK ca7a649
  Zero-1729:
    Concept ACK ca7a649

Tree-SHA512: ecf003e693ce1b63f93387f91fb101bbf6e0fa95399108c9752b4011abe1565ea8f6d0873fa3a413480b99c7eadeddb98540ddec925ae822693241987f22459c

Author: laanwj