Starting with Rclone v1.63, which is used in the Nextcloud tests for
synchronization, the client relies on the correct WebDAV endpoint url,
see https://github.com/rclone/rclone/issues/7103
* Ensure that the redis cache is actually used in the "trivial" case
(`with-postgresql-and-redis`)
* Test against all Nextcloud versions we've packaged
* Actually set a secret to make sure that the provided secret is
properly read by Nextcloud.
* Add myself as maintainer to the secret-test to make sure that I don't
miss any more changes like this that could break the functionality of
that feature.
It's supposed to be `memcache.distributed`, not an associative PHP array
named `memcache` with a key `distributed`.
This was probably never caught because the initial `grep -q` check in
the test was invalid: `redis-cli` prints nothing if no keys can be found
when not writing to a tty apparently.
