chore(deps-dev): Bump vega from 5.29.0 to 5.30.0 (#591)

Bumps [vega](https://github.com/vega/vega) from 5.29.0 to 5.30.0.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a
href="https://github.com/vega/vega/releases">vega's
releases</a>.</em></p>
<blockquote>
<h2>v5.30.0</h2>
<p>Changes since v5.29.0</p>
<p><strong>vega-functions</strong></p>
<ul>
<li>make default vega format null as &quot;null&quot; (via <a
href="https://github.com/vega/vega/issues/3926">#3926</a>).
(Thanks <a href="https://github.com/kanitw"><code>@​kanitw</code></a>
&amp; <a href="https://github.com/domoritz"><code>@​domoritz</code></a>
)!</li>
</ul>
<p><strong>docs</strong></p>
<ul>
<li>Add 4 new examples (via <a
href="https://github.com/vega/vega/issues/3851">#3851</a>).
(Thanks <a href="https://github.com/avatorl"><code>@​avatorl</code></a>
&amp; <a
href="https://github.com/domoritz"><code>@​domoritz</code></a>!)</li>
</ul>
<p><strong>monorepo</strong></p>
<ul>
<li>Deploy editor preview (via <a
href="https://github.com/vega/vega/issues/3925">#3925</a>, <a
href="https://github.com/vega/vega/issues/3931">#3931</a>).
(Thanks <a
href="https://github.com/hydrosquall"><code>@​hydrosquall</code></a>!)</li>
<li>Bump all <code>vega-*</code> deps in topological order to eliminate
version mismatches within the monorepo (via <a
href="https://github.com/vega/vega/issues/3932">#3932</a>).
(Thanks <a href="https://github.com/lsh"><code>@​lsh</code></a>!)</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="https://github.com/vega/vega/commit/d2ef8b4f7d59c02ea80129f59551550a22e0ed97"><code>d2ef8b4</code></a>
chore: v5.30.0 (<a
href="https://github.com/vega/vega/issues/3934">#3934</a>)</li>
<li><a
href="https://github.com/vega/vega/commit/247acbcafbc9522bd43b3ee5cffa5b0fab87e67c"><code>247acbc</code></a>
chore: bump all <code>vega-*</code> deps in topological order (<a
href="https://github.com/vega/vega/issues/3932">#3932</a>)</li>
<li><a
href="https://github.com/vega/vega/commit/a69f0391a3c90ad9967cc172d82ddba5a9b74741"><code>a69f039</code></a>
fix: repair deploy editor preview for vega (<a
href="https://github.com/vega/vega/issues/3931">#3931</a>)</li>
<li><a
href="https://github.com/vega/vega/commit/d2c259023f239ed7301e9de77c6e27bd4f454b88"><code>d2c2590</code></a>
docs: Add 4 new examples (<a
href="https://github.com/vega/vega/issues/3851">#3851</a>)</li>
<li><a
href="https://github.com/vega/vega/commit/11a33fbc0de9b9b45c91658708bd96ee9b00b8d6"><code>11a33fb</code></a>
build: add deploy preview of the Vega editor (<a
href="https://github.com/vega/vega/issues/3925">#3925</a>)</li>
<li><a
href="https://github.com/vega/vega/commit/ff98519cce32b776a98d01dd982467d76fc9ee34"><code>ff98519</code></a>
fix: make default vega format null as &quot;null&quot; (<a
href="https://github.com/vega/vega/issues/3926">#3926</a>)</li>
<li>See full diff in <a
href="https://github.com/vega/vega/compare/v5.29.0...v5.30.0">compare
view</a></li>
</ul>
</details>
<br />


[![Dependabot compatibility
score](https://dependabot-badges.githubapp.com/badges/compatibility_score?dependency-name=vega&package-manager=npm_and_yarn&previous-version=5.29.0&new-version=5.30.0)](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`.

[//]: # (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>

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>