Add myself to libcore OWNERS

Test: manual testing
Change-Id: I058050594721f36fc69c96292c207727b39212b7
diff --git a/OWNERS b/OWNERS
index c6b3546..0b93b60 100644
--- a/OWNERS
+++ b/OWNERS
@@ -6,6 +6,7 @@
 flooey@google.com
 narayan@google.com
 nfuller@google.com
+nikitai@google.com
 paulduffin@google.com
 peteg@google.com
 prb@google.com