Bump rackup from 2.2.1 to 2.3.1

Bumps [rackup](https://github.com/rack/rackup) from 2.2.1 to 2.3.1. <details> <summary>Changelog</summary> <p><em>Sourced from <a href="https://github.com/rack/rackup/blob/main/releases.md">rackup's changelog</a>.</em></p> <blockquote> <h1>Releases</h1> <p>All notable changes to this project will be documented in this file. For info on how to format all future additions to this file please reference <a href="https://keepachangelog.com/en/1.0.0/">Keep A Changelog</a>.</p> </blockquote> </details> <details> <summary>Commits</summary> <ul> <li><a href="https://github.com/rack/rackup/commit/f3fa1d6ada90e9e7aa1f712488ddde87ea2a2075"><code>f3fa1d6</code></a> Bump patch version.</li> <li><a href="https://github.com/rack/rackup/commit/583c7dcd2a029c54858bd502e06d61f335d5f948"><code>583c7dc</code></a> Fix WEBrick SERVER_PORT handling.</li> <li><a href="https://github.com/rack/rackup/commit/adc9596920638473cacf0161b2a3bd0e6e960f0b"><code>adc9596</code></a> Bump minor version.</li> <li><a href="https://github.com/rack/rackup/commit/8e538bee4e36b5136806ba10c83a751aa73e3134"><code>8e538be</code></a> Update the webrick handler to support <code>OPTIONS *</code> requests. (<a href="https://redirect.github.com/rack/rackup/issues/40">#40</a>)</li> <li><a href="https://github.com/rack/rackup/commit/7a3e190dc1c66487abbb1d37a92e54788fe89144"><code>7a3e190</code></a> Update workflows.</li> <li><a href="https://github.com/rack/rackup/commit/5d18f5a01a520a7f585a7802ad8987800ccd0634"><code>5d18f5a</code></a> Update spec_server.rb</li> <li><a href="https://github.com/rack/rackup/commit/c6cdd479172f042be405a36709ab27a2dff3a6e1"><code>c6cdd47</code></a> Fix references from Rack::Server to Rackup::Server in comments</li> <li><a href="https://github.com/rack/rackup/commit/e3df7cb9c44e10bb195c9bc4c0be97b7613d2c2e"><code>e3df7cb</code></a> Provide a 'Changelog' link on rubygems.org/gems/rackup</li> <li><a href="https://github.com/rack/rackup/commit/39d522608a94e76739df61dc200c93f1aadb4a58"><code>39d5226</code></a> Documentation for how to access handlers programatically.</li> <li><a href="https://github.com/rack/rackup/commit/301b6dd5f525b38acabfd2bdf38a6cd2f4ed488a"><code>301b6dd</code></a> Update <code>releases.md</code> - fixes <a href="https://redirect.github.com/rack/rackup/issues/29">#29</a>.</li> <li>See full diff in <a href="https://github.com/rack/rackup/compare/v2.2.1...v2.3.1">compare view</a></li> </ul> </details> <br /> [](https://docs.github.com/en/github/managing-security-vulnerabilities/about-dependabot-security-updates#about-compatibility-scores) You can trigger a rebase of this PR by commenting `@dependabot rebase`. [//]: # (dependabot-automerge-start) [//]: # (dependabot-automerge-end) --- <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> > **Note** > Automatic rebases have been disabled on this pull request as it has been open for over 30 days.