Bad gpg signature when trying to install winepak

[St3v3-wq]

$ flatpak remote-add --if-not-exists winepak https://dl.winepak.org/repo/winepak.flatpakrepo

error: Signature made Fri 20 Jul 2018 04:30:34 AM CEST using RSA key ID A959831C080B608F
BAD signature from " julian@richen.io"
Key expired Tue 09 Jun 2020 08:16:34 PM CEST

flatpak-1.8.3-1.fc33.x86_64
flatpak-libs-1.8.3-1.fc33.x86_64
flatpak-selinux-1.8.3-1.fc33.noarch
flatpak-session-helper-1.8.3-1.fc33.x86_64

[St3v3-wq]

See also here: https://bugzilla.redhat.com/show_bug.cgi?id=1898623

[7system7]

Any update here? Is this repo maintained? ...but, because I have to question it, then the right answer is: not maintained.