update sig-cloud-provider emails in sigs.yaml

this change adds email addresses for the chairs and tech leads.

Author: elmiko

sigs.yaml

@@ -825,16 +825,20 @@ sigs:
     - github: bridgetkromhout
       name: Bridget Kromhout
       company: Microsoft
+      email: [email protected]
     - github: elmiko
       name: Michael McCune
       company: Red Hat
+      email: [email protected]
     tech_leads:
     - github: cheftako
       name: Walter Fender
       company: Google
+      email: [email protected]
     - github: elmiko
       name: Michael McCune
       company: Red Hat
+      email: [email protected]
     emeritus_leads:
     - github: andrewsykim
       name: Andrew Sy Kim