Rename kubernetes-sig-leads mentions to leads@ since the group has moved (#5068)

* Rename kubernetes-sig-leads mentions to leads@ since the group has moved

Signed-off-by: Jorge O. Castro <[email protected]>

* Update contributors/chairs-and-techleads/README.md

Co-authored-by: Bob Killen <[email protected]>

Co-authored-by: Bob Killen <[email protected]>

Author: castrojo

communication/zoom-guidelines.md

@@ -86,7 +86,7 @@ and training.
 #### Related moderation documentation
 
 - Zoom has [documentation on how to use their moderation tools].
-- Members of the _kubernetes-sig-leads@_ group have access to an extensive
+- Members of the _leads@_ group have access to an extensive
   [best practices doc] with screenshots going over the community Zoom best
   practices.
 

contributors/chairs-and-techleads/README.md

@@ -25,7 +25,7 @@ Communication and feedback loops:
 [Need to Know email archive]  
 [Monthly meeting]  
 Slack: #chairs-and-techleads, #sig-contribex  
-Mailing list: kubernetes-sig-leads@googlegroups.com  
+Mailing list: leads@kubernetes.io  
 Github: File issues against kubernetes/community  
 
 [values]