Delete label_notify.yml

Removing this workflow as it isn't used.

.github/workflows/label_notify.yml

@@ -1,17 +0,0 @@
-name: Notify users based on issue labels
-
-on:
-  issues:
-      types: [labeled]
-  pull_requests:
-      types: [labeled]
-
-jobs:
-  notify:
-    runs-on: ubuntu-latest
-    steps:
-        - uses: jenschelkopf/issue-label-notification-action@1.3
-          with:
-             recipients: |
-                  lua=@dbaileychess
-                  c++=@aardappel