opam signing keys

[rjbou]

The current linked key expired on 28/08/2022 (see ocaml/opam.ocaml.org#25 (comment)).
For the moment, I extended its expiration date to 11/2023. The file need then to be updated on the website.

For future releases, I plan to set up another (more common) mechanism: long standing primary key and "short" subkeys (1-2 years), all registered on key servers.

[avsm]

Where is the new file @rjbou? You should be able to PR to ocaml/opam2web to update it directly now.

[tmcgilchrist]

Dockerfile includes on https://github.com/ocaml-opam/opam2web/blob/master/Dockerfile#L53 and provide the new key in https://github.com/ocaml-opam/opam2web/tree/master/ext/key. Since the process is using Docker it's possible to build the image locally and validate the keys.