Add support for in-container master for vlans

[mmirecki]

Add support for in-container master for the vlan plugin

[mmirecki]

@dougbtv @dcbw @s1061123 Could you please take a look?

[mmirecki]

/cc @dougbtv @s1061123

[dougbtv]

This seems fairly straightforward to me, at least the code changes. But, I'm also interested in what we'll provide for docs / explain the usage as well.

[mmirecki]

This seems fairly straightforward to me, at least the code changes. But, I'm also interested in what we'll provide for docs / explain the usage as well.

We have this doc PR for this: https://github.com/containernetworking/cni.dev/pull/109

[mmirecki]

Almost good. Thank you for the PR.

BTW, is there any reason why you don't add tests for 'linkInContainer' option in vlan_test.go?

Tests modified. Thanks for catching this.

[mmirecki]

@dcbw can you please take a look?

[mccv1r0]

/lgtm /approve