supported-branches.json: add refs/heads/chrome/m154

Change-Id: I33d287bb7642b653eae38066b238c24cd9bf6c74
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/1346117
Bot-Commit: chrome-branch-day <chrome-branch-day@chops-service-accounts.iam.gserviceaccount.com>

supported-branches.json

diff --git a/supported-branches.json b/supported-branches.json
index bc7c531..08a33ff 100644
--- a/supported-branches.json
+++ b/supported-branches.json
@@ -23,6 +23,10 @@
     {
       "ref": "refs/heads/chrome/m153",
       "owner": "chrome-branch-day@chops-service-accounts.iam.gserviceaccount.com"
+    },
+    {
+      "ref": "refs/heads/chrome/m154",
+      "owner": "chrome-branch-day@chops-service-accounts.iam.gserviceaccount.com"
     }
   ]
 }
\ No newline at end of file