Release v0.5.1

[geriom]

• Prepare hugo modules
• Update package.json
• Update config.yaml
• Update Changelog
• Create and test new tags
• Create and publish the new release 🎉
• Update docsy theme to dosy version v0.5.1 docsy-example#188

[geriom]

Docsy v0.5.1 released: https://github.com/google/docsy/releases/tag/v0.5.1

[deining]

@geriom: Can we please update the exampe site to the newly released version? A corresponding PR exists already. Thanks.

[geriom]

Thanks for opening that PR. Approved and merged.