v1.1.1

• Uses public docker image in docker compose file.
• Adopts semantic versioning.

v1.1

• Improves code style.
• Forces virtualenv upgrading in travis environment.
• Bumps python-telegram-bot and opencv-python versions.
• Fixes breaking changes with python-telegram-bot.
• Speeds up docker image creation.
• Adds python 3.9 support.
• Uses opencv-python-headless package.

v1.0

• Initial release.