docs: Update README.md to remove image ref (#294)

# Pull Request

Remove unused image which is returning 404.

## Description

Remove unused image. 

## License

By submitting this pull request, I confirm that my contribution is made
under the terms of the projects associated license.

README.md

@@ -6,8 +6,6 @@
 ![GitHub closed pull requests](https://img.shields.io/github/issues-pr-closed/Azure/ALZ-PowerShell-Module)
 ![GitHub contributors](https://img.shields.io/github/contributors/Azure/ALZ-PowerShell-Module)
 
-![Logo](./docs/wiki/media/Logo.png)
-
 ## Introduction
 
 This repository contains the PowerShell module and documentation for the Azure landing zones Accelerators for Bicep and Terraform. The accelerators are an opinionated implementation of the Azure Landing Zones Terraform modules, with Azure DevOps or GitHub bootstrapping.