The link should be an invite, since people without accounts won't be
able to see the channel.

Change-Id: If3554e4cd7b8ee694e06ff650101a5c003d20761
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/286892


Trust: Rebecca Stambler <rstambler@golang.org>
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
(cherry picked from commit 63d2287a)
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/286913