feat: Create dependabot.yml (#757)

Signed-off-by: Joyce <joycebrum@google.com> Co-authored-by: Brett Cannon <brett@python.org>

Author: joycebrum

.github/dependabot.yml

@@ -0,0 +1,10 @@
+version: 2
+updates:
+ - package-ecosystem: "github-actions"
+ directory: "/"
+ schedule:
+ interval: "monthly"
+ groups:
+ github-actions:
+ patterns:
+ - "*"