design/25530-notary: fix GoCenter vs Artifactory

JFrog Artifactory is the (among other things) Go module proxy
that someone might run on their own local network.
GoCenter is the publicly-available instance JFrog runs.

Change-Id: I9fa030d7571fac50eb4d84b729bd82a516e4a798
Reviewed-on: https://go-review.googlesource.com/c/proposal/+/167537
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 5d925e2..b891a9f 100644
--- a/design/25530-notary.md
+++ b/design/25530-notary.md
@@ -538,7 +538,7 @@
 
 A complete solution for notary privacy concerns is to for
 developers to access the notary only through a proxy,
-such as a local Athens instance or JFrog’s GoCenter,
+such as a local Athens instance or JFrog Artifactory instance,
 assuming those proxies add support for proxying and
 caching the Go notary service endpoints.