Use repo-specific tree_status_url in skcms

Bug: skia:12393
Change-Id: I65e62f621ddc07f0e3220682ed37844d4917b88c
Reviewed-on: https://skia-review.googlesource.com/c/skcms/+/444559
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Ravi Mistry <rmistry@google.com>
diff --git a/infra/skcq.json b/infra/skcq.json
index f2550ca..47c72ce 100644
--- a/infra/skcq.json
+++ b/infra/skcq.json
@@ -2,5 +2,6 @@
   "visibility_type": "public",
   "tasks_json_path": "infra/bots/tasks.json",
   "committer_list": "project-skia-committers",
-  "dry_run_access_list": "project-skia-tryjob-access"
+  "dry_run_access_list": "project-skia-tryjob-access",
+  "tree_status_url": "https://tree-status.skia.org/skcms/current"
 }