design/25530-notary: fix last updated

Change-Id: I1a93229b71709b5b50603485e3c7cede4d18b5f0
Reviewed-on: https://go-review.googlesource.com/c/proposal/+/165020
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
diff --git a/design/25530-notary.md b/design/25530-notary.md
index 9fcbba7..4b243e9 100644
--- a/design/25530-notary.md
+++ b/design/25530-notary.md
@@ -3,7 +3,7 @@
 Russ Cox\
 Filippo Valsorda
 
-Last updated: February 26, 2019.
+Last updated: March 4, 2019.
 
 [golang.org/design/25530-notary](https://golang.org/design/25530-notary)