Configure Dependabot to monitor GitHub Actions workflow dependencies (#294)

* Configure Dependabot to monitor GitHub Actions dependencies

Co-authored-by: thomasturrell <1552612+thomasturrell@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: thomasturrell <1552612+thomasturrell@users.noreply.github.com>

Author: Copilot

.github/dependabot.yml

@@ -11,3 +11,7 @@ updates:
       interval: "weekly"
     reviewers:
       - "berrycloud/reviewers"
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"