Add Github action workflow to notify on main jobs failures (#690)

**Context:**
It is useful to receive notifications whenever a github action workflow
running on mail fails. Github has a slack integration that can be
configured, but that sends notification for every job in any
state(started, cancelled, failed, succeeded). There is an [open
issue](integrations/slack#1563) that hasn't
been solved for 2 years.
Because of this, a manual job that triggers based on failures of
selected job on main is a better approach, and it won't need to add the
notification on each single job.

**Description of the Change:**
A new workflow is added that will send notification to a slack
channel(specified in the webhook configuration in the slack settings).

**Benefits:**
Get notification when specified jobs fails on main

**Possible Drawbacks:**
None

**Related GitHub Issues:**
None

.github/workflows/notify-failed-jobs.yaml

@@ -0,0 +1,25 @@
+name: Notify on main failures
+on:
+  workflow_run:
+    branches:
+      - main
+    types:
+      - completed
+    workflows:
+      - Build Catalyst Wheel on Linux (x86_64)
+      - Build Catalyst Wheel on macOS (arm64)
+      - Build Catalyst Wheel on macOS (x86_64)
+
+jobs:
+  on-failure:
+    runs-on: ubuntu-latest
+    if: github.event.workflow_run.conclusion == 'failure' || github.event.workflow_run.conclusion == 'timed_out'
+    steps:
+      - uses: ravsamhq/notify-slack-action@v2
+        with:
+          status: ${{ github.event.workflow_run.conclusion }}
+          notification_title: " ${{github.event.workflow_run.name}} - ${{github.event.workflow_run.conclusion}} on ${{github.event.workflow_run.head_branch}} - <${{github.server_url}}/${{github.repository}}/actions/runs/${{github.event.workflow_run.id}}|View Failure>"
+          message_format: ":fire: *${{github.event.workflow_run.name}}* ${{github.event.workflow_run.conclusion}} in <${{github.server_url}}/${{github.repository}}/${{github.event.workflow_run.head_branch}}|${{github.repository}}>"
+          footer: "Linked Repo <${{github.server_url}}/${{github.repository}}|${{github.repository}}> | <${{github.server_url}}/${{github.repository}}/actions/runs/${{github.event.workflow_run.id}}|View Failure>"
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_NOTIFICATIONS_WEBHOOK_URL }}