Merge unprivileged_userns profile: Allow full file system access

Fixes https://gitlab.com/apparmor/apparmor/-/issues/505

The profile previously permitted access to `/**`, which excludes the root
directory (`/`). This commit also gives `/` access, aligning with the
intended behavior.

Signed-off-by: Maxime Bélair <maxime.belair@canonical.com>

Closes #505
MR: https://gitlab.com/apparmor/apparmor/-/merge_requests/1626
Approved-by: Georgia Garcia <georgia.garcia@canonical.com>
Merged-by: John Johansen <john@jjmx.net>

profiles/apparmor.d/unprivileged_userns

@@ -13,7 +13,7 @@ profile unprivileged_userns {
      allow network,
      allow signal,
      allow dbus,
-     allow file rwlkm /**,
+     allow file rwlkm /{,**},
      allow unix,
      allow mqueue,
      allow ptrace,