Remove deprecated notification channel (#2330)

Co-authored-by: Rory de Zoete <rdezoete@RorysMacStudio.fritz.box>

.github/workflows/notifications.yml

@@ -1,45 +0,0 @@
-name: Send Notifications
-
-on:
-  push:
-    branches: [ main ]
-
-jobs:
-  send-notifications:
-    timeout-minutes: 30
-    name: send commit notifications
-    runs-on: ubuntu-latest
-
-    steps:
-
-      - name: Checkout
-        uses: actions/checkout@v2
-        with:
-          submodules: true
-          fetch-depth: 2
-
-      - name: Form variables for notification message
-        id: git_info_grab
-        run: |
-          git_stat=$(git show --stat=50)
-          git_stat="${git_stat//'%'/'%25'}"
-          git_stat="${git_stat//$'\n'/'%0A'}"
-          git_stat="${git_stat//$'\r'/'%0D'}"
-          git_stat="${git_stat// / }" # space -> 'Space En', as github tends to eat ordinary spaces
-          echo "::set-output name=git_stat::$git_stat"
-          echo "::set-output name=sha_short::$(git rev-parse --short HEAD)"
-          echo "##[set-output name=git_branch;]$(echo ${GITHUB_REF#refs/heads/})"
-
-      - name: Send notification
-        uses: appleboy/telegram-action@master
-        with:
-          to: ${{ secrets.TELEGRAM_TO }}
-          token: ${{ secrets.TELEGRAM_TOKEN }}
-          format: markdown
-          args: |
-            *@${{ github.actor }} pushed to* [${{ github.repository }}:${{steps.git_info_grab.outputs.git_branch}}](github.com/${{ github.repository }}/commit/${{steps.git_info_grab.outputs.sha_short }})
-
-            ```
-            ${{ steps.git_info_grab.outputs.git_stat }}
-            ```
-