qemu-build.sh: add python3-venv dependency

The latest 8.1 QEMU requires this be in the docker image now

Tested:
- Confirmed I can build latest openbmc/qemu with this

Change-Id: Ib2163840402f2034d600f419d83dbef641362cf6
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
1 file changed