add dependabot

PiperOrigin-RevId: 564386841
diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644
index 0000000..d5e7fb7
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,11 @@
+# Copyright 2023 Google Inc. All Rights Reserved.
+#
+# Distributed under MIT license.
+# See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
+
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"