it also wanted an autoremove ...ran that and got the same... then ran this
 apt-get update
$ apt-get -y install sudo wget gnupg2
$ wget -qO - https://debian.koha-community.org/koha/gpg.asc | gpg --dearmor -o /usr/share/keyrings/koha-keyring.gpg
$ apt-get update
 
and got the same.