Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 2.7.0 to 2.8.0.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a href="https://github.com/docker/build-push-action/releases">docker/build-push-action's releases</a>.</em></p>
<blockquote>
<h2>v2.8.0</h2>
<ul>
<li>Allow specifying subdirectory with default git context (<a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/531">#531</a>)</li>
<li>Add <code>cgroup-parent</code>, <code>shm-size</code>, <code>ulimit</code> inputs (<a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/501">#501</a>)</li>
<li>Don't set outputs if empty or nil (<a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/470">#470</a>)</li>
<li>docs: example to sanitize tags with metadata-action (<a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/476">#476</a>)</li>
<li>docs: wrong syntax to sanitize repo slug (<a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/475">#475</a>)</li>
<li>docs: test before pushing your image (<a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/455">#455</a>)</li>
<li>readme: remove v1 section (<a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/500">#500</a>)</li>
<li>ci: virtual env file system info (<a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/510">#510</a>)</li>
<li>dev: update workflow (<a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/499">#499</a>)</li>
<li>Bump <code>@​actions/core</code> from 1.5.0 to 1.6.0 (<a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/160">#160</a>)</li>
<li>Bump ansi-regex from 5.0.0 to 5.0.1 (<a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/469">#469</a>)</li>
<li>Bump tmpl from 1.0.4 to 1.0.5 (<a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/465">#465</a>)</li>
<li>Bump csv-parse from 4.16.0 to 4.16.3 (<a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/451">#451</a> <a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/459">#459</a>)</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a href="1814d3dfb3"><code>1814d3d</code></a> Merge pull request <a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/531">#531</a> from BeyondEvil/subdir-with-default-context</li>
<li><a href="fc5a732e0c"><code>fc5a732</code></a> Add subdirectory for Git context</li>
<li><a href="b1aeb1103e"><code>b1aeb11</code></a> Merge pull request <a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/510">#510</a> from crazy-max/venv</li>
<li><a href="e31f93ab9f"><code>e31f93a</code></a> ci: virtual env file system info</li>
<li><a href="9ed5823618"><code>9ed5823</code></a> Merge pull request <a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/501">#501</a> from crazy-max/new-inputs</li>
<li><a href="4222161e3e"><code>4222161</code></a> Merge pull request <a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/500">#500</a> from crazy-max/readme</li>
<li><a href="67ff4df4b7"><code>67ff4df</code></a> add <code>cgroup-parent</code>, <code>shm-size</code>, <code>ulimit</code> inputs</li>
<li><a href="91274a04da"><code>91274a0</code></a> sort flags</li>
<li><a href="ff329397c0"><code>ff32939</code></a> readme: remove v1 section</li>
<li><a href="04841f2a72"><code>04841f2</code></a> Merge pull request <a href="https://github-redirect.dependabot.com/docker/build-push-action/issues/499">#499</a> from crazy-max/update-workflow</li>
<li>Additional commits viewable in <a href="https://github.com/docker/build-push-action/compare/v2.7.0...v2.8.0">compare view</a></li>
</ul>
</details>
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