[Python-checkins] Let dependabot create PRs against the maintenance branches (GH-22992)

[miss-islington]

https://github.com/python/cpython/commit/0603f8087abab4d56fd275051ab3fd76a477539a
commit: 0603f8087abab4d56fd275051ab3fd76a477539a
branch: master
author: Mariatta <Mariatta at users.noreply.github.com>
committer: miss-islington <31488909+miss-islington at users.noreply.github.com>
date: 2020-12-15T11:04:55-08:00
summary:

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.

files:
M .github/dependabot.yml

diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index e90677b9f775a..d9cbb3c7ec385 100644
--- 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"