Create dependabot.yml

Configure weekly updates for `package.json` and `Dockerfile`

.github/dependabot.yml

@@ -0,0 +1,13 @@
+# 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: "npm"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+  - package-ecosystem: "docker"
+    directory: "/"
+    schedule:
+      interval: "weekly"