OWNERS: Remove tobiast, agampe, add paulduffin.

This set of owners is more up-to-date.

Test: Manually inspected the result.
Bug: 152399425
Change-Id: I2e49bf30625ef8593b639c52f89dc00fb5bcb879
diff --git a/OWNERS b/OWNERS
index 7dfdbbb..aa3cdc3 100644
--- a/OWNERS
+++ b/OWNERS
@@ -1,7 +1,6 @@
 # Default owners are top 3 or more active developers of the past 1 or 2 years
 # or people with more than 10 commits last year.
 # Please update this list if you find better owner candidates.
-agampe@google.com
 ccross@android.com
-tobiast@google.com
 jdesprez@google.com
+paulduffin@google.com