Dependency upgrades and tooling tweaks

Keeping dependencies up to date:

• Upgrade jest from 23.6.0 to 24.1.0
• Upgrade eslint-config-prettier from 3.3.0 to 4.0.0
• Upgrade eslint-plugin-import from 2.14.0 to 2.16.0
• Upgrade prettier from 1.15.3 to 1.16.4
• Upgrade eslint-plugin-jest from 22.1.2 to 22.2.2
• Upgrade botkit from 0.6.21 to 0.7.2
• Upgrade eslint-plugin-prettier from 3.0.0 to 3.0.1
• Upgrade eslint from 5.10.0 to 5.13.0

Linting and testing tooling is now dogfooded within this repository.

Initial open source release

This release marks the initial open source release of this module. It can be installed from npm at @shopkeep/bot-scripts.