Add dependabot configuration

I noticed some of the actions are behind latest version, so I enabled dependabot and lets see if we can track and update them.

Author: dawitnida

.github/dependabot.yml

@@ -0,0 +1,8 @@
+version: 2
+updates:
+  # Maintain dependencies for GitHub Actions
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: weekly
+    open-pull-requests-limit: 5