ICU-20496 Run the Exhaustive Tests on "maint" branches as well.
diff --git a/.ci-builds/.azure-exhaustive-tests.yml b/.ci-builds/.azure-exhaustive-tests.yml
index 0a4365c..89470a1 100644
--- a/.ci-builds/.azure-exhaustive-tests.yml
+++ b/.ci-builds/.azure-exhaustive-tests.yml
@@ -9,14 +9,15 @@
     lfs: true
     fetchDepth: 1
 
-# Only run the exhaustive tests on the master branch, and batch up
-# any pending changes so that we will only have at most one build
-# running at a given time.
+# Only run the exhaustive tests on the master and maint branches, and
+# also batch up any pending changes so that we will only have at most
+# one build running at a given time (since they take a long time).
 trigger:
   batch: true
   branches:
     include:
     - master
+    - maint/*
 
 jobs:
 #-------------------------------------------------------------------------