リリースの手順を明文化する

.github/PULL_REQUEST_TEMPLATE/releasing.md

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+<!--
+PR title format: Release vN.N.N
+
+Please rewrite the versions in this template before submitting the PR:
+- Current version: X.X.X
+- New version: N.N.N
+-->
+
+## ToDo before merging
+- [ ] [Update `README.md`](#update-readmemd)
+- [ ] [Update `CHANGELOG.md`](#update-changelogmd)
+- [ ] [Verify version numbers that need to be updated](#verify-version-numbers-that-need-to-be-updated)
+
+### Update `README.md`
+- Update `LernaVersion` to a new version
+
+### Update `CHANGELOG.md`
+- Add a section for the new version
+- Update a link for `[Unreleased]`
+
+### Verify version numbers that need to be updated
+
+```shell
+git grep --fixed-string X.X.X
+...
+```
+
+## ToDo after merging
+- [ ] [Push a tag](#push-a-tag)
+- [ ] [Check Maven Central Repository](#check-maven-central-repository)
+- [ ] [Create a release](#create-a-release)
+
+### Push a tag
+
+```shell
+git tag vN.N.N
+git push origin vN.N.N
+```
+
+### Check Maven Central Repository
+
+[Maven Central Repository](https://repo1.maven.org/maven2/com/lerna-stack/)
+
+**NOTE**
+- They will appear about 10 minutes after publishing on [release workflow](https://github.com/lerna-stack/lerna-app-library/actions/workflows/release.yml)
+- It requires more time to be able to find them with searching (about 2 hours max)
+
+### Create a release
+
+Create a release from the following URL:
+
+https://github.com/lerna-stack/lerna-app-library/releases/new
+
+- **Choose a tag**: select the tag you created 
+- **Release title**: same as the tag
+- **Describe this release**:
+    ```markdown
+    See [CHANGELOG.md] for details.
+
+    [CHANGELOG.md]: https://github.com/lerna-stack/lerna-app-library/blob/main/CHANGELOG.md#vNNN---YYYY-MM-DD <!-- write an anchor for the release version -->
+    ```

RELEASING.md

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+# Releasing
+
+This document shows how to release a new version.
+
+## 1. Create a new branch
+
+```shell
+git checkout main
+git pull
+git checkout -b release/vN.N.N # replace N.N.N to a new release version
+```
+
+## 2. Create a new PR
+
+Create a new PR with the [`releasing.md` PR Template](./.github/PULL_REQUEST_TEMPLATE/releasing.md) after pushing the branch:
+
+```shell
+git push
+```
+
+Ask a maintainer to review the PR after submitting it.