Add dependabot config

.github/dependabot.yml

@@ -0,0 +1,20 @@
+# To get started with Dependabot version updates, you'll need to specify which
+# package ecosystems to update and where the package manifests are located.
+# Please see the documentation for all configuration options:
+# https://docs.github.com/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file
+
+# https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/configuring-dependabot-version-updates
+
+version: 2
+updates:
+  - package-ecosystem: 'composer'
+    directory: '/'
+    schedule:
+      interval: 'monthly'
+    groups:
+      # group all updates that are minor or path versions
+      upgrade-batch:
+        applies-to: version-updates
+        update-types:
+          - 'minor'
+          - 'patch'