Add Matrix chatrooms to README.md

Bug: None
Change-Id: I72f7df3326cc91d7306db13145cdae9e50982bf2
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/20380
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
diff --git a/README.md b/README.md
index 92e7728..a6800ee 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,8 @@
  - [Dawn's bug tracker](https://bugs.chromium.org/p/dawn/issues/entry) if you find issues with Dawn.
  - [Dawn's mailing list](https://groups.google.com/forum/#!members/dawn-graphics) for other discussions related to Dawn.
  - [Dawn's source code](https://dawn.googlesource.com/dawn)
+ - [Dawm's Matrix chatroom](https://matrix.to/#/#webgpu-dawn:matrix.org) for live discussion around contributing or using Dawn.
+ - [WebGPU's Matrix chatroom](https://matrix.to/#/#WebGPU:matrix.org)
 
 ## Documentation table of content