chore: update template files

Author: twilio-dx

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,10 @@
+contact_links:
+  - name: Twilio SendGrid Support
+    url: https://support.sendgrid.com
+    about: Get Support
+  - name: Stack Overflow
+    url: https://stackoverflow.com/questions/tagged/csharp-http-client+or+sendgrid+csharp
+    about: Ask questions on Stack Overflow
+  - name: Documentation
+    url: https://sendgrid.com/docs/for-developers/
+    about: View Reference Documentation