Lock issues and pull requests after close

Ref https://github.com/roboll/helmfile/issues/1824

.github/workflows/lock.yaml

@@ -0,0 +1,30 @@
+# Copyright 2022 The Helmfile Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+name: 'Lock closed'
+on:
+  schedule:
+  - cron: '0 0 * * *'
+
+jobs:
+  lock:
+    runs-on: 'ubuntu-latest'
+    steps:
+    - uses: 'dessant/lock-threads@v2'
+      with:
+        github-token: '${{ github.token }}'
+        issue-lock-inactive-days: 1
+        issue-lock-reason: 'resolved'
+        pr-lock-inactive-days: 1
+        pr-lock-reason: 'resolved'