feat: auto assign author to assignees workflow (#6)

* feat: auto assign author to assignees workflow

* fix: rename workflow to workflows

* test: test assignees

* fix: restore pr-template types synchronized to opened

.github/workflows/auto-assign-assignees.yml

@@ -0,0 +1,26 @@
+name: auto assign author to assignees
+
+on:
+  pull_request:
+    types: [opened]
+
+jobs:
+  add-assignees:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+      - name: Add assignee
+        uses: actions/github-script@v3
+        with:
+          github-token: ${{secrets.GITHUB_TOKEN}}
+          script: |
+            github.issues.addAssignees({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              assignees: [context.payload.pull_request.user.login]
+            })