Maintenance: Enable dependabot

Author: tschaefer

.github/dependabot.yml

@@ -0,0 +1,19 @@
+---
+version: 2
+updates:
+- package-ecosystem: bundler
+  directory: "/"
+  schedule:
+    interval: daily
+  groups:
+    bundler:
+      patterns:
+      - "*"
+- package-ecosystem: github-actions
+  directory: "/"
+  schedule:
+    interval: daily
+  groups:
+    gh-actions:
+      patterns:
+      - "*"