Upgrade to GitHub-native Dependabot

.github/dependabot.yml

@@ -0,0 +1,25 @@
+version: 2
+updates:
+- package-ecosystem: npm
+  directory: "/"
+  schedule:
+    interval: daily
+  open-pull-requests-limit: 10
+  ignore:
+  - dependency-name: jsdoc-to-markdown
+    versions:
+    - 7.0.0
+- package-ecosystem: bundler
+  directory: "/"
+  schedule:
+    interval: daily
+  open-pull-requests-limit: 10
+  ignore:
+  - dependency-name: rubocop
+    versions:
+    - 1.10.0
+    - 1.11.0
+    - 1.12.0
+    - 1.12.1
+    - 1.9.0
+    - 1.9.1