✨ feat: Implement auto-assign for new issues with GitHub Actions

This commit introduces a new feature where new issues and pull requests are automatically assigned using GitHub Actions. An auto-assign.yml configuration file has been created for this purpose. This will streamline the management of issues and pull requests.

Related Issue: YJU-OKURA#7

.github/workflows/auto-assign.yml

@@ -0,0 +1,19 @@
+name: Auto Assign
+on:
+  issues:
+    types: [opened]
+  pull_request:
+    types: [opened]
+jobs:
+  run:
+    runs-on: ubuntu-latest
+    permissions:
+      issues: write
+      pull-requests: write
+    steps:
+    - name: 'Auto-assign issue'
+      uses: pozil/auto-assign-issue@v1
+      with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          assignees: yuminn-k
+          numOfAssignee: 1