[ci] Switch the fetch head to 'main' (#4653)
The default branch is now `main`, so that should be the default base
revision for the tooling to compare against.
diff --git a/.cirrus.yml b/.cirrus.yml
index 024ce59..bbaa39e 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -9,7 +9,7 @@
tool_setup_template: &TOOL_SETUP_TEMPLATE
tool_setup_script:
- - git fetch origin master # To set FETCH_HEAD for "git merge-base" to work
+ - git fetch origin main # To set FETCH_HEAD for "git merge-base" to work
- cd script/tool
- dart pub get