Bumps [serialize-javascript](https://github.com/yahoo/serialize-javascript) from 1.7.0 to 2.1.1.
<details>
<summary>Release notes</summary>

*Sourced from [serialize-javascript's releases](https://github.com/yahoo/serialize-javascript/releases).*

> ## v2.1.0
> - Add `ignoreFunction` option ([@&#8203;realdennis](https://github.com/realdennis), [#58](https://github-redirect.dependabot.com/yahoo/serialize-javascript/issues/58))
> 
> ## v2.0.0
> - re-landed [#54](https://github-redirect.dependabot.com/yahoo/serialize-javascript/issues/54) with bump major version (see: [#57](https://github-redirect.dependabot.com/yahoo/serialize-javascript/issues/57))
> 
> ## v1.9.1
> - Revert [#54](https://github-redirect.dependabot.com/yahoo/serialize-javascript/issues/54) for breaking changes (see: https://github-redirect.dependabot.com/yahoo/serialize-javascript/issues/57)
> - Bump mocha from 5.2.0 to 6.2.0 ([#56](https://github-redirect.dependabot.com/yahoo/serialize-javascript/issues/56))
> 
> ## v1.9.0
> * support serialize undefined ([@&#8203;nqdy666](https://github.com/nqdy666), [#54](https://github-redirect.dependabot.com/yahoo/serialize-javascript/issues/54))
> * Update Node.js versions to tests
> 
> ## v1.8.0
> - Enhanced object literals don't have arrows ([@&#8203;jowenjowen](https://github.com/jowenjowen), [#51](https://github-redirect.dependabot.com/yahoo/serialize-javascript/issues/51))
</details>
<details>
<summary>Commits</summary>

- [`433fc9c`](yahoo/serialize-javascript@433fc9c) 2.1.1
- [`16a68ab`](yahoo/serialize-javascript@16a68ab) Merge pull request from GHSA-h9rv-jmmf-4pgx
- [`3bab6de`](yahoo/serialize-javascript@3bab6de) Bump mocha from 6.2.1 to 6.2.2 ([#60](https://github-redirect.dependabot.com/yahoo/serialize-javascript/issues/60))
- [`7a6b13d`](yahoo/serialize-javascript@7a6b13d) Bump mocha from 6.2.0 to 6.2.1 ([#59](https://github-redirect.dependabot.com/yahoo/serialize-javascript/issues/59))
- [`40cf793`](yahoo/serialize-javascript@40cf793) Migrate to nyc from istanbul
- [`31c98ad`](yahoo/serialize-javascript@31c98ad) 2.1.0
- [`9b47a96`](yahoo/serialize-javascript@9b47a96) Feat. New option `ignoreFunction` according to issue#32 ([#58](https://github-redirect.dependabot.com/yahoo/serialize-javascript/issues/58))
- [`c65dd4a`](yahoo/serialize-javascript@c65dd4a) 2.0.0
- [`1879481`](yahoo/serialize-javascript@1879481) Revert "Revert "support serialize undefined ([#54](https://github-redirect.dependabot.com/yahoo/serialize-javascript/issues/54))""
- [`9ee6b1c`](yahoo/serialize-javascript@9ee6b1c) 1.9.1
- Additional commits viewable in [compare view](yahoo/serialize-javascript@v1.7.0...v2.1.1)
</details>
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