luci: update branch console links in chromium-header.

Change-Id: I61205e4a5a80405f8570691fc2c28ac3a0c228ec
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2132593Reviewed-by: Garrett Beaty <gbeaty@chromium.org>
Commit-Queue: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#755551}

infra/config/consoles/chromium-header.textpb

@@ -164,13 +164,13 @@ links {
 links {
   name: "Branch Consoles"
   links {
-    text: "beta"
-    url: "/p/chromium/g/main-beta/console"
+    text: "m81"
+    url: "/p/chromium/g/main-m81/console"
     alt: "Beta branch console"
   }
   links {
-    text: "stable"
-    url: "/p/chromium/g/main-stable/console"
+    text: "m80"
+    url: "/p/chromium/g/main-m80/console"
     alt: "Stable branch console"
   }
   links {