feat: check for the existence of a description field

it is not mandatory in the sigma standard but
mandatory for this repository

rules/windows/powershell/powershell_script/powershell_azurehound_commands.yml

@@ -1,16 +1,17 @@
 title: AzureHound PowerShell Commands
 id: 83083ac6-1816-4e76-97d7-59af9a9ae46e
 status: experimental
-description: 
+description: Detects the execution of AzureHound in PowerShell, a tool to gather data from Azure for BloodHound
 references:
     - https://github.com/BloodHoundAD/BloodHound/blob/master/Collectors/AzureHound.ps1
     - https://bloodhound.readthedocs.io/en/latest/data-collection/azurehound.html
 author: Austin Songer (@austinsonger)
 date: 2021/10/23
+modified: 2022/01/12
 logsource:
     product: windows
     category: ps_script
-    definition: Script Block Logging must be enable
+    definition: Script Block Logging must be enabled
 detection:
     selection:
         ScriptBlockText|contains: Invoke-AzureHound