ci: add dependabot.yml (#21)

Author: DeepDiver1975

.github/dependabot.yml

@@ -0,0 +1,21 @@
+version: 2
+updates:
+  - package-ecosystem: "composer"
+    directory: "/"
+    target-branch: "master"
+    schedule:
+      interval: "weekly"
+    open-pull-requests-limit: 5
+    labels:
+      - "dependencies"
+      - "automated"
+
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    target-branch: "master"
+    schedule:
+      interval: "weekly"
+    open-pull-requests-limit: 5
+    labels:
+      - "dependencies"
+      - "automated"