Travis Build failing for armv6/7 arm64 images

```
error: failed to solve: rpc error: code = Unknown desc = executor failed running [/dev/.buildkit_qemu_emulator /bin/sh -c pip install -r /opt/cameraevents/requirements.txt]: exit code: 2
The command "./.travis/deploy.sh" exited with 1.
```

Only happens in arm32v6/7 and arm64.  AMD 64 builds quite happily.
First seen in :#22 