Update readme.md

Solutions/Microsoft Defender for Office 365/Playbooks/O365DefenderPlaybooks/o365-DeleteMaliciousInboxRule/readme.md

@@ -56,7 +56,7 @@ Once deployment is complete, you will need to authorize each connection.
 1. Select the Keyvault resource where you have stored the secret
 2. Click on Access policies Blade
 3. Click on Create
-4. Under Secret permissions columun , Select Get , List from "Secret Management Operations"
+4. Under Secret permissions column , Select Get , List from "Secret Management Operations"
 5. Click next to go to Principal tab and choose your deployed playbook name
 6. Click Next leave application tab as it is .
 7. Click Review and create