chore: Allow dependabot to upgrade other GHAs (#3513)

Co-authored-by: Jacob Fuss <[email protected]>

Author: jfuss

.github/dependabot.yml

@@ -0,0 +1,13 @@
+version: 2
+updates:
+
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    commit-message:
+      prefix: chore
+      include: scope
+    reviewers:
+      - aws/sae-enterprise
+    open-pull-requests-limit: 10