Markdown fix

* Markdown fix

docs/upgrade.md

@@ -4,7 +4,7 @@ Splunk Connect for Syslog is updated regularly using a CI/CD development process
 must be taken into account prior and after an upgrade.  Ensure to follow specific instructions below to ensure a smooth
 transition to a new version of SC4S in production.
 
-###Upgrade process
+## Upgrade process
 Check the current version of SC4S by running ```sudo <docker or podman> logs SC4S```. For the latest version, use the
 `latest` tag for the SC4S image in the sc4s.service unit file:
 ```