chcore: update logo

Author: saurabhraghuvanshii

landscape.yml

@@ -57,7 +57,7 @@ categories:
             description:  A specification for describing event data in a common way. 
           - name: Open Contracting Data Standard
             homepage_url: https://standard.open-contracting.org/latest/en/
-            logo: Open-Contracting-Data-Standard.svg 
+            logo: Open-Contracting-Data-Standard.png 
             description: The Open Contracting Data Standard (OCDS) enables disclosure of data and documents at all stages of the contracting process by defining a common data model.
 
       - name: Adopters