Change the wording

Co-authored-by: Christoph Blecker <[email protected]>

Author: sanposhiho

sigs.yaml

@@ -2874,7 +2874,7 @@ sigs:
       email: [email protected]
     - github: sanposhiho
       name: Kensei Nakada
-      company: (Individual contributor)
+      company: Independent
       email: [email protected]
     tech_leads:
     - github: dom4ha