Enable Dependabot for Docker and GitHub Actions

AFAIK (and this was new to me) Dependabot is not active by default.

This enables it for all dependencies here, so it scans and suggests updates.

GitHub Actions is as far as I see not yet used, but well… easy enough to do that hehe soon…

.github/dependabot.yml

@@ -0,0 +1,16 @@
+version: 2
+updates:
+  - package-ecosystem: "docker"
+    directory: "/"
+    schedule:
+      interval: "daily"
+  - package-ecosystem: "npm"
+    directory: "/"
+    schedule:
+      interval: "daily"
+  # Maintain dependencies for GitHub Actions
+  # src: https://github.com/marketplace/actions/build-and-push-docker-images#keep-up-to-date-with-github-dependabot
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"