ci(workflow): remove notify-workflow job (no longer needed)

We will now use GitHub Discussions as the sole channel for
release notifications and forward these to Discord if needed.

.github/workflows/notify-release.yml

@@ -5,22 +5,6 @@ on:
     types: [published]
 
 jobs:
-  notify-discord:
-    runs-on: ubuntu-22.04
-    steps:
-      - name: Notify Discord
-        uses: fjogeleit/http-request-action@v1
-        with:
-          url: ${{ secrets.DISCORD_WEBHOOK }}
-          method: "POST"
-          customHeaders: '{"Content-Type": "application/json"}'
-          data: |-
-            {
-              "avatar_url": "https://avatars.githubusercontent.com/u/98603954?v=4",
-              "username": "Bot Anik",
-              "content": "🚨 A new version of @${{github.repository}} ${{ github.event.release.tag_name }} has been released! 🎉\n\n👉 Changelog: https://github.com/${{ github.repository }}/releases/tag/${{ github.event.release.tag_name }}\n👉 Official repo: https://github.com/${{ github.repository }}"
-            }
-
   notify-github-discussion:
     runs-on: ubuntu-22.04
     steps: