Install Slack Drivers Problems

This was a clean install of botman studio.
>php artisan botman:install-driver slack

Installing driver "Slack"
Using version ^2.1 for botman/driver-slack

./composer.json has been updated

Loading composer repositories with package information

Updating dependencies (including require-dev)

Your requirements could not be resolved to an installable set of packages.

Problem 1
- Installation request for react/stream (locked at v1.0.0) -> satisfiable by react/stream[v1.0.0].
- Installation request for react/event-loop (locked at v1.0.0) -> satisfiable by react/event-loop[v1.0.0].
- Conclusion: don't install mpociot/slack-client 1.1
- botman/driver-slack 2.1.0 requires mpociot/slack-client ~1.0 -> satisfiable by mpociot/slack-client[1.0, 1.1].
- botman/driver-slack 2.1.1 requires mpociot/slack-client ~1.0 -> satisfiable by mpociot/slack-client[1.0, 1.1].
- botman/driver-slack 2.1.2 requires mpociot/slack-client ~1.0 -> satisfiable by mpociot/slack-client[1.0, 1.1].
- botman/driver-slack 2.1.3 requires mpociot/slack-client ~1.0 -> satisfiable by mpociot/slack-client[1.0, 1.1].
- Conclusion: don't install mpociot/slack-client 1.0
- Installation request for botman/driver-slack ^2.1 -> satisfiable by botman/driver-slack[2.1.0, 2.1.1, 2.1.2, 2.1.3].

Installation failed, reverting ./composer.json to its original content.
Error installing driver "Slack"