Bitrise Start Build
https://github.com/bitrise-steplib/bitrise-step-build-router-start
Bitrise Deploy Step
https://github.com/bitrise-io/steps-deploy-to-bitrise-io
Slack Message step
https://github.com/bitrise-io/steps-slack-message
Expose an Environment Variable and use it another step
https://devcenter.bitrise.io/tips-and-tricks/expose-environment-variable/