Add Dependabot for the new Mozart composer directory

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

.github/dependabot.yml

@@ -38,3 +38,18 @@ updates:
   allow:
   - dependency-type: direct
   - dependency-type: indirect
+- package-ecosystem: composer
+  directory: "/vendor-bin/mozart/"
+  schedule:
+      interval: weekly
+      day: saturday
+      time: "03:00"
+      timezone: Europe/Paris
+  open-pull-requests-limit: 10
+  labels:
+      - 3. to review
+      - dependencies
+      - php
+  allow:
+      - dependency-type: direct
+      - dependency-type: indirect