content: add link to Go Module Proxy talk

Change-Id: I03257e7d8e1a243e63374af79d06585f229a6638
Reviewed-on: https://go-review.googlesource.com/c/blog/+/310518
Trust: Katie Hockman <katie@golang.org>
Run-TryBot: Katie Hockman <katie@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

content/experiment.article

diff --git a/content/experiment.article b/content/experiment.article
index 286077e..cf2ee69 100644
--- a/content/experiment.article
+++ b/content/experiment.article
@@ -1195,8 +1195,7 @@
 the Go team at Google has [launched a proxy](https://groups.google.com/forum/#!topic/golang-announce/0wo8cOhGuAI) that serves
 as a public mirror of all open-source Go packages,
 and Go 1.13 will use that proxy by default when in module mode.
-Katie Hockman gave a talk about this system at Gophercon 2019.
-(We’ll add a link here when the video becomes available.)
+Katie Hockman gave a [talk about this system at Gophercon 2019](https://youtu.be/KqTySYYhPUE).
 
 **Go Modules Status**