centered diagram in UC 1 page

Signed-off-by: George M Dias <GDIAS@MITRE.ORG>

Author: georgedias

src/courses/delta/04.md

@@ -26,6 +26,7 @@ Suppose we want to update our [Windows Server 2019 inspec profile repository](ht
 #### Step 1: Collect necessary files:
 1. Download or clone the Windows Server 2019 profile repository to your system.
 2. Download the [latest STIG](https://public.cyber.mil/stigs/downloads/) place the XCCDF XML file into your working directory.
+
 ![File directory containing an inspec profile and an XCCDF XML file](../../assets/img/Delta_Class/Delta_Files_1.png)
 
 #### Step 2: Generate a profile summary