chore(deps): update gradle/actions action to v6.1.0 (#1875)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [gradle/actions](https://redirect.github.com/gradle/actions) | action
| minor | `v6.0.1` → `v6.1.0` |

---

### Release Notes

<details>
<summary>gradle/actions (gradle/actions)</summary>

###
[`v6.1.0`](https://redirect.github.com/gradle/actions/releases/tag/v6.1.0)

[Compare
Source](https://redirect.github.com/gradle/actions/compare/v6.0.1...v6.1.0)

#### New: Basic Cache Provider

A new MIT-licensed **Basic Caching** provider is now available as an
alternative to the proprietary **Enhanced Caching** provided by
`gradle-actions-caching`. Choose Basic Caching by setting
`cache-provider: basic` on `setup-gradle` or `dependency-submission`
actions.

- Built on `@actions/cache` -- fully open source
- Caches `~/.gradle/caches` and `~/.gradle/wrapper` directories
- Cache key derived from build files (`*.gradle*`,
`gradle-wrapper.properties`, etc.)
- Clean cache on build file changes (no restore keys, preventing stale
entry accumulation)

**Limitations vs Enhanced Caching:** No cache cleanup, no deduplication
of cached content, cached content is fixed unless build files change.

#### Revamped Licensing & Distribution Documentation

- New **DISTRIBUTION.md** documents the licensing of each component
(particularly Basic Caching vs Enhanced Caching)
- Simplified licensing notices in README, docs, and runtime log output
- Clear usage tiers: Enhanced Caching is free for public repos and in
Free Preview for private repos

#### What's Changed

- Use a unique cache entry for wrapper-validation test by
[@&#8203;bigdaz](https://redirect.github.com/bigdaz) in
[#&#8203;921](https://redirect.github.com/gradle/actions/pull/921)
- Update Dependencies by
[@&#8203;bigdaz](https://redirect.github.com/bigdaz) in
[#&#8203;922](https://redirect.github.com/gradle/actions/pull/922)
- Update dependencies and resolve npm vulnerabilities by
[@&#8203;bigdaz](https://redirect.github.com/bigdaz) in
[#&#8203;933](https://redirect.github.com/gradle/actions/pull/933)
- Add open-source 'basic' cache provider and revamp licensing
documentation by [@&#8203;bigdaz](https://redirect.github.com/bigdaz) in
[#&#8203;930](https://redirect.github.com/gradle/actions/pull/930)
- Restructure caching documentation for basic and enhanced providers by
[@&#8203;bigdaz](https://redirect.github.com/bigdaz) in
[#&#8203;934](https://redirect.github.com/gradle/actions/pull/934)

**Full Changelog**:
<gradle/actions@v6.0.1...v6.1.0>

</details>

---

### Configuration

📅 **Schedule**: (in timezone Asia/Tokyo)

- Branch creation
  - At any time (no schedule defined)
- Automerge
  - At any time (no schedule defined)

🚦 **Automerge**: Enabled.

♻ **Rebasing**: Whenever PR is behind base branch, or you tick the
rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update
again.

---

- [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check
this box

---

This PR was generated by [Mend Renovate](https://mend.io/renovate/).
View the [repository job
log](https://developer.mend.io/github/line/line-bot-sdk-java).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0My4xMTAuMiIsInVwZGF0ZWRJblZlciI6IjQzLjExMC4yIiwidGFyZ2V0QnJhbmNoIjoibWFzdGVyIiwibGFiZWxzIjpbImRlcGVuZGVuY3kgdXBncmFkZSJdfQ==-->

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/publish.yml

@@ -27,7 +27,7 @@ jobs:
           distribution: 'temurin'
 
       - name: Validate Gradle wrapper
-        uses: gradle/actions/wrapper-validation@39e147cb9de83bb9910b8ef8bd7fff0ee20fcd6f # v6.0.1
+        uses: gradle/actions/wrapper-validation@50e97c2cd7a37755bbfafc9c5b7cafaece252f6e # v6.1.0
 
       - name: Show Version Number
         id: version