Upgrade to GitHub-native Dependabot (overtrue#418)

Author: dependabot-preview[bot]

.github/dependabot.yml

@@ -0,0 +1,12 @@
+version: 2
+updates:
+- package-ecosystem: composer
+  directory: "/"
+  schedule:
+    interval: daily
+    time: "21:00"
+  open-pull-requests-limit: 10
+  ignore:
+  - dependency-name: overtrue/wechat
+    versions:
+    - ">= 5.a, < 6"