build(deps): bump @contentful/content-source-maps (#2531)

Bumps the production-dependencies group with 1 update: [@contentful/content-source-maps](https://github.com/contentful/live-preview).


Updates `@contentful/content-source-maps` from 0.11.20 to 0.11.21
- [Release notes](https://github.com/contentful/live-preview/releases)
- [Commits](https://github.com/contentful/live-preview/compare/@contentful/content-source-maps@0.11.20...@contentful/content-source-maps@0.11.21)

---
updated-dependencies:
- dependency-name: "@contentful/content-source-maps"
  dependency-version: 0.11.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: production-dependencies
...

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Author: dependabot[bot]