Bump lints from 5.1.1 to 6.0.0 in /code_sharing/server (#2619)

Bumps [lints](https://github.com/dart-lang/core/tree/main/pkgs) from 5.1.1 to 6.0.0.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a href="https://github.com/dart-lang/core/releases">lints's releases</a>.</em></p>
<blockquote>
<h2>package:lints v6.0.0</h2>
<ul>
<li><code>core</code>:
<ul>
<li>added <a href="https://dart.dev/lints/strict_top_level_inference">strict_top_level_inference</a> (<a href="https://redirect.github.com/dart-lang/core/issues/836">dart-lang/core#836</a>)</li>
</ul>
</li>
<li><code>recommended</code>:
<ul>
<li>added <a href="https://dart.dev/lints/unnecessary_underscores">unnecessary_underscores</a> (<a href="https://redirect.github.com/dart-lang/core/issues/856">dart-lang/core#856</a>)</li>
</ul>
</li>
<li>Require Dart 3.8.</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a href="228112c086"><code>228112c</code></a> prep to publish 6.0.0 of package:lints (<a href="https://github.com/dart-lang/core/tree/main/pkgs/issues/878">#878</a>)</li>
<li><a href="e32c7b96b9"><code>e32c7b9</code></a> Fix StreamGroup.broadcast() close() not completing when streams close. (<a href="https://github.com/dart-lang/core/tree/main/pkgs/issues/876">#876</a>)</li>
<li><a href="af37fe54c3"><code>af37fe5</code></a> Adds <code>[Heap]PriorityQueue.of</code> constructor. (<a href="https://github.com/dart-lang/core/tree/main/pkgs/issues/734">#734</a>)</li>
<li><a href="635dfa32c2"><code>635dfa3</code></a> [collection] explicitly make BoolList abstract interface (<a href="https://github.com/dart-lang/core/tree/main/pkgs/issues/875">#875</a>)</li>
<li><a href="a6e81e0b74"><code>a6e81e0</code></a> Make URL strategy better at recognizing URLs. (<a href="https://github.com/dart-lang/core/tree/main/pkgs/issues/873">#873</a>)</li>
<li><a href="61e677100b"><code>61e6771</code></a> Check for mandatory when using option (<a href="https://github.com/dart-lang/core/tree/main/pkgs/issues/871">#871</a>)</li>
<li><a href="db610bb595"><code>db610bb</code></a> Adjust the implements clause of IntX (<a href="https://github.com/dart-lang/core/tree/main/pkgs/issues/866">#866</a>)</li>
<li><a href="22d8879fcb"><code>22d8879</code></a> [package:lints] fix the changelog (<a href="https://github.com/dart-lang/core/tree/main/pkgs/issues/867">#867</a>)</li>
<li><a href="9f43210084"><code>9f43210</code></a> add strict_top_level_inference to the core lint set (<a href="https://github.com/dart-lang/core/tree/main/pkgs/issues/864">#864</a>)</li>
<li><a href="15c7fe9958"><code>15c7fe9</code></a> add unnecessary_underscores to recommended (<a href="https://github.com/dart-lang/core/tree/main/pkgs/issues/863">#863</a>)</li>
<li>Additional commits viewable in <a href="https://github.com/dart-lang/core/commits/lints-v6.0.0/pkgs">compare view</a></li>
</ul>
</details>
<br />

[![Dependabot compatibility score](https://dependabot-badges.githubapp.com/badges/compatibility_score?dependency-name=lints&package-manager=pub&previous-version=5.1.1&new-version=6.0.0)](https://docs.github.com/en/github/managing-security-vulnerabilities/about-dependabot-security-updates#about-compatibility-scores)

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting `@dependabot rebase`.

---

<details>
<summary>Dependabot commands and options</summary>
<br />

You can trigger Dependabot actions by commenting on this PR:
- `@dependabot rebase` will rebase this PR
- `@dependabot recreate` will recreate this PR, overwriting any edits that have been made to it
- `@dependabot merge` will merge this PR after your CI passes on it
- `@dependabot squash and merge` will squash and merge this PR after your CI passes on it
- `@dependabot cancel merge` will cancel a previously requested merge and block automerging
- `@dependabot reopen` will reopen this PR if it is closed
- `@dependabot close` will close this PR and stop Dependabot recreating it. You can achieve the same result by closing it manually
- `@dependabot show <dependency name> ignore conditions` will show all of the ignore conditions of the specified dependency
- `@dependabot ignore this major version` will close this PR and stop Dependabot creating any more for this major version (unless you reopen the PR or upgrade to it yourself)
- `@dependabot ignore this minor version` will close this PR and stop Dependabot creating any more for this minor version (unless you reopen the PR or upgrade to it yourself)
- `@dependabot ignore this dependency` will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself)

</details>

code_sharing/server/pubspec.yaml

@@ -15,5 +15,5 @@ dependencies:
 
 dev_dependencies:
   http: ^1.0.0
-  lints: ^5.0.0
+  lints: ^6.0.0
   test: ^1.15.0