docs: Update contact link in runtime README

This PR updates the contact link in the runtime README document.

Fixes #3854

Signed-off-by: Gabriela Cervantes <gabriela.cervantes.tellez@intel.com>

src/runtime/README.md

@@ -158,7 +158,7 @@ See [the community repository](https://github.com/kata-containers/community).
 
 ### Contact
 
-See [how to reach the community](https://github.com/kata-containers/community/blob/master/CONTRIBUTING.md#contact).
+See [how to reach the community](https://github.com/kata-containers/community/blob/main/CONTRIBUTING.md#contact).
 
 ## Further information