manibuilder: Automatically create `manibuilder` network bridge

Create a network bridge for all manibuilder containers. We'll add a
service container with access to a local Git repository later.

Change-Id: Idb03c21dbd12bef59a2c683e169015e286c04d11
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/70910
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: Nico Huber <nico.h@gmx.de>
1 file changed