chore: configure Dependabot for GitHub Actions updates (#112)

Sets up Dependabot to automatically check for updates to 
GitHub Actions on a weekly basis, ensuring that the project 
remains up-to-date with the latest dependencies and security 
fixes.

Co-authored-by: gagb <gagb@users.noreply.github.com>

.github/dependabot.yml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"