Add myself to kubernetes-sigs

I'm already member of the kubernetes org, and the request form says I can add myself directly to other orgs..

Author: porridge

config/kubernetes-sigs/org.yaml

@@ -689,6 +689,7 @@ members:
 - pmalek
 - pohly
 - poonam-lamba
+- porridge
 - Pradumnasaraf
 - Prajyot-Parab
 - prankulmahajan