Bump proc-macro-crate from 2.0.1 to 3.0.0 (#2876)

Bumps [proc-macro-crate](https://github.com/bkchr/proc-macro-crate) from
2.0.1 to 3.0.0.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a
href="https://github.com/bkchr/proc-macro-crate/releases">proc-macro-crate's
releases</a>.</em></p>
<blockquote>
<h2>v3.0.0</h2>
<h2>What's Changed</h2>
<ul>
<li>Release 3.0.0 by <a
href="https://github.com/bkchr"><code>@​bkchr</code></a> in <a
href="https://redirect.github.com/bkchr/proc-macro-crate/pull/47">bkchr/proc-macro-crate#47</a></li>
</ul>
<p><strong>Full Changelog</strong>: <a
href="https://github.com/bkchr/proc-macro-crate/compare/v2.0.1...v3.0.0">https://github.com/bkchr/proc-macro-crate/compare/v2.0.1...v3.0.0</a></p>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="https://github.com/bkchr/proc-macro-crate/commit/c9671b5f8c307c50aab61e2352450a620d236d8b"><code>c9671b5</code></a>
Merge pull request <a
href="https://redirect.github.co...