Create dependabot.yml (#30)

copied from https://github.com/storytold/photocraft/blob/main/.github/dependabot.yml

.github/dependabot.yml

@@ -0,0 +1,15 @@
+version: 2
+updates:
+  # Maintain GitHub Actions workflows
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"
+      time: "06:00"
+      timezone: "America/New_York"
+    groups:
+      actions:
+        patterns:
+          - "*"
+    commit-message:
+      prefix: "ci(deps)"