Update generating-hash-for-a-token.md

Fixed powershell block to base64 encode the output

Author: benhorton

data/reusables/audit_log/generating-hash-for-a-token.md

@@ -14,6 +14,6 @@ Param (
 $hasher = [System.Security.Cryptography.HashAlgorithm]::Create('sha256')
 $hash = $hasher.ComputeHash([System.Text.Encoding]::UTF8.GetBytes($ClearString))
 
-$hashString = [System.BitConverter]::ToString($hash)
-$hashString.Replace('-', '')
+$hashString = [System.Convert]::ToBase64String($hash)
+$hashString
 ```