android: fix contributing doc

Change-Id: I628376759b958898bb2163dde0ad3eb9407be7d1
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 70dc1b5..cec73cc 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -15,7 +15,7 @@
 4. What did you expect to see?
 5. What did you see instead?
 
-Sensitive security-related issues should be reported to [ehg@google.com](mailto:ehg@google.com).
+Sensitive security-related issues should be reported to [upspin-security@googlegroups.com](mailto:upspin-security@googlegroups.com).
 
 ## Contributing code