Ensure that when testing on stable Cirrus is upgraded to latest on iOS (flutter#2211)

collinjackson · Park Sung Min · commit 49ac7182b006 · 2019-12-17T22:59:28.000+09:00
* Ensure that stable is upgraded to latest

* Fix file that shouldn't have been committed
diff --git a/.cirrus.yml b/.cirrus.yml
@@ -84,6 +84,8 @@ task:
   setup_script:
     - pod repo update
   upgrade_script:
+    - flutter channel stable
+    - flutter upgrade
     - flutter channel master
     - flutter upgrade
     - git fetch origin master
