Update npm packages using Dependabot

.github/dependabot.yml

@@ -0,0 +1,26 @@
+version: 2
+
+updates:
+  # Update npm packages
+  - package-ecosystem: npm
+    directory: /
+    open-pull-requests-limit: 10
+
+    reviewers:
+      - alphagov/design-system-developers
+
+    # Schedule run every Monday, local time
+    schedule:
+      interval: weekly
+      time: '10:30'
+      timezone: 'Europe/London'
+
+    versioning-strategy: increase
+
+    allow:
+      # Include direct package.json updates
+      - dependency-type: direct
+
+      # Include indirect browser data updates
+      # https://caniuse.com
+      - dependency-name: caniuse-lite