Update dependency gradle to v8.13 (#27)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [gradle](https://gradle.org)
([source](https://redirect.github.com/gradle/gradle)) | minor | `8.12.1`
-> `8.13` |

---

### Release Notes

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

###
[`v8.13`](https://redirect.github.com/gradle/gradle/compare/v8.12.1...v8.13.0)

[Compare
Source](https://redirect.github.com/gradle/gradle/compare/v8.12.1...v8.13.0)

</details>

---

### Configuration

📅 **Schedule**: Branch creation - "before 4am on Monday" in timezone
CET, Automerge - At any time (no schedule defined).

🚦 **Automerge**: Disabled by config. Please merge this manually once you
are satisfied.

♻ **Rebasing**: Whenever PR becomes conflicted, 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

---

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Author: renovate[bot]

gradle/wrapper/gradle-wrapper.jar

@@ -1,7 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionSha256Sum=8d97a97984f6cbd2b85fe4c60a743440a347544bf18818048e611f5288d46c94
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.12.1-bin.zip
+distributionSha256Sum=20f1b1176237254a6fc204d8434196fa11a4cfb387567519c61556e8710aed78
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.13-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME