docs(v2): Add react-hooks.org to showcase

[imbhargav5]

Motivation

I built react-hooks.org entirely with docusaurus and I would like to add it to it's showcase.

Have you read the Contributing Guidelines on pull requests?

Yes

Test Plan

Just changed the a JSON file. I don't know if it requires any tests.

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[github-actions]

Size Change: +17 B (0%)

Total Size: 156 kB

ℹ️ View Unchanged

Filename	Size	Change
website/build/assets/css/styles.********.css	17.6 kB	0 B
website/build/assets/js/main.********.js	109 kB	+14 B (0%)
website/build/blog/2017/12/14/introducing-docusaurus/index.html	21.7 kB	+3 B (0%)
website/build/docs/introduction/index.html	180 B	0 B
website/build/index.html	6.94 kB	0 B

_{compressed-size-action}

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[github-actions]

⚡️ Lighthouse report for the changes in this PR:

Category	Score
🟠 Performance	85
🟢 Accessibility	96
🟢 Best practices	100
🟢 SEO	100
🟢 PWA	95

Lighthouse ran on https://deploy-preview-4172--docusaurus-2.netlify.app/classic/

[slorber]

thanks :)