Upgrade to GitHub-native Dependabot

.dependabot/config.yml

@@ -1,11 +0,0 @@
-version: 1
-
-update_configs:
-  - package_manager: ruby:bundler
-    directory: "/"
-    update_schedule: live
-    default_labels:
-      - dependencies
-    default_reviewers:
-      - goodevilgenius
-    target_branch: master

.github/dependabot.yml

@@ -0,0 +1,21 @@
+version: 2
+updates:
+- package-ecosystem: bundler
+  directory: "/"
+  schedule:
+    interval: daily
+    time: "11:00"
+  open-pull-requests-limit: 10
+  target-branch: master
+  reviewers:
+  - goodevilgenius
+  labels:
+  - dependencies
+  ignore:
+  - dependency-name: sprockets
+    versions:
+    - ">= 4.a, < 5"
+  - dependency-name: nokogiri
+    versions:
+    - 1.11.1
+    - 1.11.2