- Adds version to version.txt in root
- adds update-version.sh which updates version in frontend/package.json and backend/btrixcloud/version.py
- frontend: loads version from $VERSION env var, ../version.txt or package.json
- ci: on new github release, pushes webrecorder/browsertrix-backend and webrecorder/browsertrix-frontend images to Dockerhub with current version, as well as latest.
- version set to 1.1.0-beta.0
- closes#357
