design/25530-sumdb: move 25530-notary to 25530-sumdb

Part of renaming away from notary.

Change-Id: Id5cd82fa404b61392cea8827857f4a10e6c5e2e4
Reviewed-on: https://go-review.googlesource.com/c/proposal/+/173542
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
diff --git a/design/25530-notary.md b/design/25530-sumdb.md
similarity index 99%
rename from design/25530-notary.md
rename to design/25530-sumdb.md
index 9cddd3a..ca897aa 100644
--- a/design/25530-notary.md
+++ b/design/25530-sumdb.md
@@ -5,7 +5,7 @@
 
 Last updated: March 4, 2019.
 
-[golang.org/design/25530-notary](https://golang.org/design/25530-notary)
+[golang.org/design/25530-sumdb](https://golang.org/design/25530-sumdb)
 
 Discussion at [golang.org/issue/25530](https://golang.org/issue/25530).