[infra] Update go.sum

I didn't follow all of the necessary steps in
https://skia-review.googlesource.com/c/skia/+/279038

Change-Id: I4210b09025f5c32664c81a1f3f6c51310b904589
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/279044
Reviewed-by: Ravi Mistry <rmistry@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
diff --git a/go.sum b/go.sum
index 85cad25..8459e8e2 100644
--- a/go.sum
+++ b/go.sum
@@ -304,6 +304,7 @@
 github.com/golang/mock v1.4.0/go.mod h1:UOMv5ysSaYNkG+OFQykRIcU/QvvxJf3p21QfJ2Bt3cw=
 github.com/golang/mock v1.4.1 h1:ocYkMQY5RrXTYgXl7ICpV0IXwlEQGwKIsery4gyXa1U=
 github.com/golang/mock v1.4.1/go.mod h1:UOMv5ysSaYNkG+OFQykRIcU/QvvxJf3p21QfJ2Bt3cw=
+github.com/golang/mock v1.4.3 h1:GV+pQPG/EUUbkh47niozDcADz6go/dUwhVzdUQHIVRw=
 github.com/golang/mock v1.4.3/go.mod h1:UOMv5ysSaYNkG+OFQykRIcU/QvvxJf3p21QfJ2Bt3cw=
 github.com/golang/protobuf v0.0.0-20161109072736-4bd1920723d7/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=