change name of master to main

Author: PGijsbers

docs/intro/Governance.md

@@ -6,7 +6,7 @@ This is a meritocratic, consensus-based community project. Anyone with an intere
 
 ### Roles And Responsibilities
 
-<img src="https://github.com/openml/docs/raw/master/docs/img/OpenML-governance.png" alt="governance" width="300"/>
+<img src="https://github.com/openml/docs/raw/main/docs/img/OpenML-governance.png" alt="governance" width="300"/>
 
 #### Contributors