Adjust logo entries to align with newer schema

Author: kingthorin

project.owasp.yaml

@@ -13,9 +13,7 @@ community:
     url: https://app.slack.com/client/T04T40NHX/CJ2QDHLRJ
     description: '#testing-guide on OWASP slack'
 logo:
-  - small: "https://github.com/OWASP/wstg/blob/master/.github/www/assets/202006-owasp_material/Github/Github%20-%20Shield%20400x400%20-%20Gradient%20%E2%80%93%201.png"
     medium: "https://github.com/OWASP/wstg/blob/master/.github/www/assets/202006-owasp_material/Github/Github%20-%20Shield%20400x400%20-%20Gradient%20%E2%80%93%201.png"
-    large: "https://github.com/OWASP/wstg/blob/master/.github/www/assets/202006-owasp_material/Github/Github%20-%20Shield%20400x400%20-%20Gradient%20%E2%80%93%201.png"
 level: 4
 license:
   - CC-BY-SA-4.0