Update dependabot-changeset workflow to trigger on dependencies label (#290)

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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: IzumiSy <982850+IzumiSy@users.noreply.github.com>

Author: Copilot

.github/workflows/dependabot-changeset.yaml

@@ -2,13 +2,13 @@ name: Add Changeset to Dependabot PRs
 
 on:
   pull_request:
-    types: [opened, synchronize]
+    types: [opened, synchronize, labeled]
 
 concurrency: ${{ github.workflow }}-${{ github.ref }}
 
 jobs:
   add-changeset:
-    if: github.actor == 'dependabot[bot]'
+    if: contains(github.event.pull_request.labels.*.name, 'dependencies')
     runs-on: ubuntu-latest
     permissions:
       contents: write