Let dependabot create PRs against the maintenance branches (GH-22992)

With this, we don't have to manually trigger backport whenever there is update to GitHub Actions dependencies.

diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index e90677b9f775a720bd397c5e835b624e4fc362de..d9cbb3c7ec38548f1af1e8edb045bfe36d6e0341 100644 (file)
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -7,3 +7,7 @@ updates:
     labels:
       - "skip issue"
       - "skip news"
+    target_branch:
+      - "master"
+      - "3.9"
+      - "3.8"