[INFRA] Create a workflow to test sending message to Slack (#84)

Author: tbouffard

.github/workflows/slack-send-message.yml

@@ -0,0 +1,53 @@
+name: Slack send message
+on:
+  workflow_dispatch:
+    inputs:
+      channel-or-user:
+        description: 'Send a message to a channel or a user (prefer usage of id instead of name).'
+        default: 'CSF7TG6N5'
+        type: string
+        required: true
+
+jobs:
+  build:
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Send message to Slack
+        uses: slackapi/[email protected]
+        with:
+          channel-id: ${{ github.event.inputs.channel-or-user }}
+          payload: |
+            {
+              "blocks": [
+                {
+                  "type": "header",
+                  "text": {
+                    "type": "plain_text",
+                    "text": ":mega: This is a test from the ${{github.repository}} repository",
+                    "emoji": true
+                  }
+                },
+                {
+                  "type": "divider"
+                },
+                {
+                  "type": "section",
+                  "text": {
+                    "type": "mrkdwn",
+                    "text": "- available <https://github.com/${{github.repository}}/releases|Releases> :heavy_check_mark: \n - Check packages published on <https://www.npmjs.com/package/bpmn-visualization|NPM> :heavy_check_mark:"
+                  }
+                },
+                {
+                  "type": "divider"
+                },
+                {
+                  "type": "section",
+                  "text": {
+                    "type": "mrkdwn",
+                    "text": "See the next steps <https://github.com/${{github.repository}}/blob/master/docs/contributors/maintainers.md#github-issues-milestones-and-projects-update|here> :arrow_left:"
+                  }
+                }
+              ]
+            }
+        env:
+          SLACK_BOT_TOKEN: ${{ secrets.SLACK_BOT_TOKEN }}

README.md

@@ -14,6 +14,7 @@ GitHub pages environment generated by this repository
 - [execute job on secrets availability](.github/workflows/execute-depending-on-secrets-availability.yml): use in surge deployments to avoid trying to create deployments for external contributors and dependabot (surge token secret not available)
 - [fill github draft releases](.github/workflows/fill-gh-draft-release.yml): experiment the release-drafter configuration (used in bpmn-visualization)
 - [Generate Documentation API](.github/workflows/generate-documentation-api.yml): generate a TypeDoc API documentation and push to github-pages (for bpmn-visualization)
+- [Slack send message](.github/workflows/slack-send-message.yml): send a message to a Slack channel or user
 - [workflow dispatch](.github/workflows/workflow-dispatch.yml): run job depending on if the workflow is triggered from the `master` branch or another branch
 
 ### Release simulation