build: setup dependabot

GitHub Actions Updates:
  - Monitors workflow files for action version updates (like actions/checkout@v4)
  - Updates composite action dependencies referenced in action.yml
  - Runs weekly on Mondays at 6 AM
  - Creates up to 10 PRs for GitHub Actions updates

  Docker Updates:
  - Monitors the ghcr.io/cdviz-dev/cdviz-collector container image reference
  - Checks for new versions of the base container
  - Runs weekly on Mondays at 6 AM
  - Creates up to 5 PRs for Docker updates

  Features:
  - ✅ Automatic PR creation for dependency updates
  - ✅ Proper labeling (dependencies, github-actions, docker)
  - ✅ Conventional commit messages with chore prefix
  - ✅ Reviewer assignment to cdviz-dev
  - ✅ Rate limiting to prevent PR spam

Author: davidB

.github/dependabot.yml

@@ -0,0 +1,35 @@
+version: 2
+updates:
+  # GitHub Actions dependencies
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+      day: "monday"
+      time: "06:00"
+    open-pull-requests-limit: 10
+    reviewers:
+      - "cdviz-dev"
+    labels:
+      - "dependencies"
+      - "github-actions"
+    commit-message:
+      prefix: "chore"
+      include: "scope"
+
+  # Docker dependencies (for the container image referenced in action.yml)
+  - package-ecosystem: "docker"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+      day: "monday"
+      time: "06:00"
+    open-pull-requests-limit: 5
+    reviewers:
+      - "cdviz-dev"
+    labels:
+      - "dependencies"
+      - "docker"
+    commit-message:
+      prefix: "chore"
+      include: "scope"