Bump tokio from 1.24.2 to 1.25.0 in /cmd/pinniped-proxy (#5930)

Bumps [tokio](https://github.com/tokio-rs/tokio) from 1.24.2 to 1.25.0.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a
href="https://github.com/tokio-rs/tokio/releases">tokio's
releases</a>.</em></p>
<blockquote>
<h2>Tokio v1.25.0</h2>
<h1>1.25.0 (January 28, 2023)</h1>
<h3>Fixed</h3>
<ul>
<li>rt: fix runtime metrics reporting (<a
href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/5330">#5330</a>)</li>
</ul>
<h3>Added</h3>
<ul>
<li>sync: add <code>broadcast::Sender::len</code> (<a
href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/5343">#5343</a>)</li>
</ul>
<h3>Changed</h3>
<ul>
<li>fs: increase maximum read buffer size to 2MiB (<a
href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/5397">#5397</a>)</li>
</ul>
<p><a
href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/5330">#5330</a>:
<a
href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/5330">tokio-rs/tokio#5330</a>
<a
href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/5343">#5343</a>:
<a
href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/5343">tokio-rs/tokio#5343</a>
<a
href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/5397">#5397</a>:
<a
href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/5397">tokio-rs/tokio#5397</a></p>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li>See full diff in <a
href="https://github.com/tokio-rs/tokio/commits/tokio-1.25.0">compare
view</a></li>
</ul>
</details>
<br />


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