Improve bash completion for `--credential-spec`
Improve bash completion for `--credential-spec`

This option is Windows specific and should be only available if the
daemon runs on Windows.

Signed-off-by: Harald Albers <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@albersweb.de>

ashfall/cli,redpanda/cli,allencloud/cli,cpuguy83/cli,redpanda/cli,dnephin/cli,Zebrilee/cli,thaJeztah/cli,cpuguy83/cli,allencloud/cli,dnephin/cli,docker/cli,ashfall/cli,thaJeztah/cli,docker/cli,Zebrilee/cli