Replace slack with discord |

See:
- cucumber/common#2195
- https://github.com/orgs/cucumber/discussions/2197

CONTRIBUTING.md

@@ -152,12 +152,12 @@ Looking for something simple to begin with? Look at issues with the label
 ### Having trouble getting started with the code? We're here to help!
 
 If you have trouble setting-up your development environment, or getting started
-with the code, you can join us on [Slack][community-slack]. You will find there
+with the code, you can join us on [Discord][community-discord]. You will find there
 a lot of contributors.
 
 Full-time maintainers are also available. We would be please to have 1:1 pairing
 sessions to help you getting started. Look for Luke Hill or Matt Wynne on
-[Slack][community-slack].
+[Discord][community-discord].
 
 ### Additional documentation and notice
 
@@ -169,7 +169,7 @@ You can find additional documentation in the [docs](./docs) directory such as
 
 <!-- Links -->
 
-[community-slack]: https://cucumberbdd.slack.com/
+[community-discord]: https://cucumber.io/docs/community/get-in-touch/#discord
 [cucumber-ruby]: https://github.com/cucumber/cucumber-ruby
 [cucumber-ruby-core]: https://github.com/cucumber/cucumber-ruby-core
 [cucumber-ruby-core-issues]: https://github.com/cucumber/cucumber-ruby-core/search?q=is%3Aissue

README.md

@@ -119,7 +119,7 @@ processing: it should pass ✓
 ## Documentation and support
 
 - Getting started with Cucumber, writing features, step definitions, and more: https://cucumber.io/docs
-- Slack: [register for an account](https://cucumberbdd-slack-invite.herokuapp.com/) then head over to [#intro](https://cucumberbdd.slack.com/messages/C5WD8SA21/)
+- Discord ([invite link here](https://cucumber.io/docs/community/get-in-touch/#discord))
 - `cucumber-core` overview: [docs/ARCHITECTURE.md](docs/ARCHITECTURE.md)
 - How to work with local repositories for `cucumber-gherkin`, `cucumber-messages` or `cucumber-ruby`: [CONTRIBUTING.md#working-with-local-cucumber-dependencies](./CONTRIBUTING.md#working-with-local-cucumber-dependencies)