[ci.yaml] Add roller (#88048)

diff --git a/TESTOWNERS b/TESTOWNERS
index 555a144..80fe85c 100644
--- a/TESTOWNERS
+++ b/TESTOWNERS
@@ -210,6 +210,7 @@
 # https://github.com/flutter/flutter/issues/82068
 #
 # build_tests @zanderso @flutter/tool
+# ci_yaml flutter roller @caseyhillers @flutter/infra
 # flutter_plugins @stuartmorgan @flutter/plugin
 # framework_tests @HansMuller @flutter/framework
 # tool_integration_tests @zanderso @flutter/tool