This fix tries to address the issue raised in 29975 where
it was not possible to specify `attachable` flag for networks
in compose format.
NOTE: Compose format aleady supports `labels` in networks.
This fix adds the support of `attachable` for compose v3.1 format.
Additiona unit tests have been updated and added.
This fix fixes 29975.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
- Make sure we use the correct network name for external ones.
- Make the default network overridable and only creates networks that
are used by services — so that default network is only created if a
service doesn't declare a network.
Signed-off-by: Vincent Demeester <vincent@sbr.pm>
