Included githubactions in the dependabot config (#2544)

This should help with keeping the GitHub actions updated on new releases. This will also help with keeping it secure.

Dependabot helps in keeping the supply chain secure https://docs.github.com/en/code-security/dependabot

GitHub actions up to date https://docs.github.com/en/code-security/dependabot/working-with-dependabot/keeping-your-actions-up-to-date-with-dependabot

https://github.com/ossf/scorecard/blob/main/docs/checks.md#dependency-update-tool

.github/dependabot.yml

@@ -12,3 +12,10 @@ updates:
       - dependency-name: pry-stack_explorer
         versions:
           - ">= 5.0"
+  - package-ecosystem: github-actions
+    directory: "/"
+    schedule:
+      interval: monthly
+      time: "08:00"
+      timezone: America/New_York
+    open-pull-requests-limit: 10