* Upgrade alpine to 3.15
* Add executability test to entrypoint for too old dockers
Signed-off-by: Andrew Thornton <art27@cantab.net>
* Update docker/rootless/usr/local/bin/docker-entrypoint.sh
Co-authored-by: zeripath <art27@cantab.net>
docker/root/usr/bin/entrypoint already allows for the specification
of USER, USER_UID, USER_GID. But since AllowedUsers is hardcoded in
sshd_config, one cannot log in as a user different ftom git.
This change substitutes ${USER} for git in the sshd_config template.
Signed-off-by: Jeronimo Pellegrini <j_p@aleph0.info>