chore: dependabot doesn't support bun, add a job

.github/dependabot.yml

@@ -1,11 +1,28 @@
-# To get started with Dependabot version updates, you'll need to specify which
-# package ecosystems to update and where the package manifests are located.
-# Please see the documentation for all configuration options:
-# https://docs.github.com/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file
+name: 'Dependabot: Update bun.lockb'
 
-version: 2
-updates:
-  - package-ecosystem: "" # See documentation for possible values
-    directory: "/" # Location of package manifests
-    schedule:
-      interval: "weekly"
+on:
+  pull_request:
+    paths:
+      - 'package.json'
+
+permissions:
+  contents: write
+
+jobs:
+  update-bun-lockb:
+    name: 'Update bun.lockb'
+    if: github.actor == 'dependabot[bot]'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: oven-sh/setup-bun@v1
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          ref: ${{ github.event.pull_request.head.ref }}
+      - run: |
+          bun install
+          git add bun.lockb
+          git config --global user.name 'dependabot[bot]'
+          git config --global user.email 'dependabot[bot]@users.noreply.github.com'
+          git commit --amend --no-edit 
+          git push --force