CI: Add Dependabot configuration for Composer

.github/dependabot.yml

@@ -0,0 +1,16 @@
+# 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/github/administering-a-repository/configuration-options-for-dependency-updates
+
+version: 2
+updates:
+  - package-ecosystem: "composer"
+    directory: "/"
+    schedule:
+      interval: "monthly"
+    # Prefix all commit messages with "Composer" plus its scope, that is, a
+    # list of updated dependencies
+    commit-message:
+      prefix: "Composer"
+      include: "scope"