Add GitHub Actions to Dependabot configuration

Author: timea-solid

.github/dependabot.yml

@@ -9,3 +9,8 @@ updates:
     directory: "/" # Location of package manifests
     schedule:
       interval: "weekly"
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      # Check for updates to GitHub Actions every week
+      interval: "weekly"