Merge pull request #821 from ranocha/hr/dependabot

enable dependabot for GitHub actions

Author: ChrisRackauckas

.github/dependabot.yml

@@ -1,6 +1,7 @@
+# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
 version: 2
 updates:
   - package-ecosystem: "github-actions"
-    directory: "/"
+    directory: "/" # Location of package manifests
     schedule:
-      interval: "daily"
+      interval: "weekly"