Update example.md
Update example configuration file to use the current format, `communities` section has been renamed to `bgp-communities`.
@@ -21,7 +21,7 @@ each set of addresses:
```yaml
# Rest of config omitted for brevity
-communities:
+bgp-communities:
# Our datacenter routers understand a "VPN only" BGP community.
# Announcements tagged with this community will only be propagated
# through the corporate VPN tunnel back to developer offices.
