Bump browserslist, @storybook/addon-docs and @storybook/html

Bumps [browserslist](https://github.com/browserslist/browserslist) to 4.21.3 and updates ancestor dependencies [browserslist](https://github.com/browserslist/browserslist), [@storybook/addon-docs](https://github.com/storybookjs/storybook/tree/HEAD/addons/docs) and [@storybook/html](https://github.com/storybookjs/storybook/tree/HEAD/app/html). These dependencies need to be updated together.


Updates `browserslist` from 4.14.2 to 4.21.3
- [Release notes](https://github.com/browserslist/browserslist/releases)
- [Changelog](https://github.com/browserslist/browserslist/blob/main/CHANGELOG.md)
- [Commits](browserslist/browserslist@4.14.2...4.21.3)

Updates `@storybook/addon-docs` from 6.1.21 to 6.5.12
- [Release notes](https://github.com/storybookjs/storybook/releases)
- [Changelog](https://github.com/storybookjs/storybook/blob/v6.5.12/CHANGELOG.md)
- [Commits](https://github.com/storybookjs/storybook/commits/v6.5.12/addons/docs)

Updates `@storybook/html` from 6.1.21 to 6.5.12
- [Release notes](https://github.com/storybookjs/storybook/releases)
- [Changelog](https://github.com/storybookjs/storybook/blob/v6.5.12/CHANGELOG.md)
- [Commits](https://github.com/storybookjs/storybook/commits/v6.5.12/app/html)

---
updated-dependencies:
- dependency-name: browserslist
  dependency-type: indirect
- dependency-name: "@storybook/addon-docs"
  dependency-type: direct:development
- dependency-name: "@storybook/html"
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]