.github: remove issue notifier

.github/workflows/issue_notifier.yml

@@ -1,20 +0,0 @@
-name: Notify users based on issue labels
-
-on:
-  issues:
-      types: [labeled]
-  pull_request_target:
-      types: [labeled]
-
-jobs:
-  notify:
-    runs-on: ubuntu-latest
-    steps:
-        - uses: bugobliterator/issue-label-notification-action@master
-          with:
-             recipients: |
-                  CAN=@bugobliterator
-                  AP_Periph=@bugobliterator
-                  ChibiOS=@bugobliterator
-                  Compass=@bugobliterator
-                  bootloader=@bugobliterator