docs: add 'New service integration request' to new issue template (#266)

Signed-off-by: Alexander Matyushentsev <[email protected]>

Author: Alexander Matyushentsev

.github/ISSUE_TEMPLATE/config.yml

@@ -1,6 +1,9 @@
 blank_issues_enabled: false
 
 contact_links:
+  - name: New service integration request
+    url: https://github.com/argoproj/notifications-engine/issues/new
+    about: Create ticket in https://github.com/argoproj/notifications-engine repository
   - name: Have you read the docs?
     url: https://argocd-notifications.readthedocs.io/
     about: Much help can be found in the docs