[autoroll] Switch Catapult roller chat notifications to "warning" level

Bug: chromium:931194
Change-Id: I6c58f34c3af2c6ccebecb1c1a996f4b66194a264
Reviewed-on: https://skia-review.googlesource.com/c/191583
Reviewed-by: Ravi Mistry <rmistry@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
diff --git a/autoroll/config/catapult-chromium.json b/autoroll/config/catapult-chromium.json
index 1f471f2..222d136 100644
--- a/autoroll/config/catapult-chromium.json
+++ b/autoroll/config/catapult-chromium.json
@@ -42,7 +42,7 @@
   "maxRollFrequency": "0m",
   "notifiers": [
     {
-      "filter": "info",
+      "filter": "warning",
       "chat": {
         "room": "speed-operations"
       },