chore: Add milestone action (#18)

.github/workflows/milestone.yaml

@@ -0,0 +1,34 @@
+# Description:
+#   - Add milestone to a merged PR or closed issue.
+
+name: Milestone Action
+on:
+  issues:
+    types: [closed]
+  pull_request_target:
+    types: [closed]
+
+# Fix GraphQL: Resource not accessible by integration (updatePullRequest)
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  update-milestone:
+    runs-on: ubuntu-latest
+    name: Milestone Update
+    steps:
+      - name: Set Milestone for PR
+        uses: hustcer/milestone-action@main
+        if: github.event.pull_request.merged == true
+        with:
+          action: bind-pr
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      - name: Set Milestone for Issue
+        uses: hustcer/milestone-action@main
+        if: github.event.issue.state == 'closed'
+        with:
+          action: bind-issue
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}