chore: add npm and docker to dependabot

- Monitor npm dependencies for security updates
- Monitor Docker base images for updates

Author: StuMason

.github/dependabot.yml

@@ -22,3 +22,26 @@ updates:
       time: "09:00"
       timezone: Europe/London
     open-pull-requests-limit: 5
+
+  - package-ecosystem: npm
+    directory: /
+    schedule:
+      interval: weekly
+      day: monday
+      time: "09:00"
+      timezone: Europe/London
+    open-pull-requests-limit: 10
+    groups:
+      minor-and-patch:
+        update-types:
+          - minor
+          - patch
+
+  - package-ecosystem: docker
+    directory: /
+    schedule:
+      interval: weekly
+      day: monday
+      time: "09:00"
+      timezone: Europe/London
+    open-pull-requests-limit: 5