Allow dependabot to check GitHub actions monthly (GH-22787)

Let Dependabot update GitHub Actions dependency once a month.

Here's reference to the dependabot configs.

https://docs.github.com/en/free-pro-team@latest/github/administering-a-repository/keeping-your-actions-up-to-date-with-github-dependabot

diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644 (file)
index 0000000..8ac6b8c
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "monthly"