Upgrade to GitHub-native Dependabot

Author: dependabot-preview[bot]

.github/dependabot.yml

@@ -0,0 +1,18 @@
+version: 2
+updates:
+- package-ecosystem: bundler
+  directory: "/"
+  schedule:
+    interval: daily
+    time: "13:00"
+  open-pull-requests-limit: 10
+  ignore:
+  - dependency-name: json
+    versions:
+    - "> 2.1.0"
+  - dependency-name: json
+    versions:
+    - "> 2.2.0"
+  - dependency-name: json
+    versions:
+    - ">= 2.3.a, < 2.4"