[INFRA] Make the slack notifications work again

[tbouffard]

IMPORTANT:

• the problem impacts all slack notifications in all repositories of the organization
• notifications can be tested with the a test workflow available in the https://github.com/process-analytics/github-actions-playground/ repository (it uses a test channel by default but we can also target the regular channel by setting the workflow input)

The issue has been detected during the 0.42.0 release. We usually received a slack message when the npm package is available. Instead, the workflow run failed with an authentication error

https://github.com/process-analytics/bpmn-visualization-js/actions/runs/6530992692/job/17731344072

Run slackapi/slack-github-action@v1.24.0
[WARN]  web-api:WebClient:0 The top-level `text` argument is missing in the request payload for a chat.postMessage call - It's a best practice to always provide a `text` argument when posting a message. The `text` is used in places where the content cannot be rendered such as: system push notifications, assistive technology such as screen readers, etc.
Error: Error: An API error occurred: invalid_auth

[tbouffard]

✔️ The problem has been fixed 🎉

It was due to the slack token no longer being valid. Once updated, it was possible to send messages again. See the following task executions (posting message on 2 different channels):

• https://github.com/process-analytics/github-actions-playground/actions/runs/6532061081/job/17734582900
• https://github.com/process-analytics/github-actions-playground/actions/runs/6532098366/job/17734634216

Note: the configuration for all repositories of the GitHub organization has been updated.