chore: set host networking in builder example

Signed-off-by: Marco Nenciarini <[email protected]>

Author: mnencia

Diff for: BUILD.md

@@ -35,6 +35,7 @@ docker buildx create \
   --name docker-container \
   --driver docker-container \
   --use \
+  --driver-opt network=host \
   --bootstrap
 ```