Comment 19 for bug 1782221

@theopensourcerer: Comment #2 shows how to set a MAC address on a Netplan interface:
https://bugs.launchpad.net/netplan/+bug/1782221/comments/2

You must delete the interface before running `netplan apply` for the setting to take effect. If your interface is `br0`, run `ip link delete br0 ; netplan apply`.

Note that a reboot is NOT required; what matters is deleting the affected interface so that Netplan can properly recreate it.

I wrote an example here: https://superuser.com/a/1389344/83694