chore: replace doc sample .pdf file by .xlsx to solve Crowdin issue

[slorber]

Motivation

Crowdin decided to transform pdf to html files recently and there's no way to fix our site's deploy without using the UI interface.

Hopefully, using a .zip instead of a .pdf file for our doc examples should fix it

[netlify]

✔️ [V2]

🔨 Explore the source changes: a8e58e1

🔍 Inspect the deploy log: https://app.netlify.com/sites/docusaurus-2/deploys/617be9eb9593f1000734cca3

😎 Browse the preview: https://deploy-preview-5823--docusaurus-2.netlify.app

[github-actions]

⚡️ Lighthouse report for the changes in this PR:

Category	Score
🟢 Performance	98
🟢 Accessibility	98
🟢 Best practices	100
🟢 SEO	100
🟢 PWA	95

Lighthouse ran on https://deploy-preview-5823--docusaurus-2.netlify.app/

[github-actions]

Size Change: 0 B

Total Size: 847 kB

ℹ️ View Unchanged

Filename	Size
website/.docusaurus/globalData.json	38 kB
website/build/assets/css/styles.********.css	94 kB
website/build/assets/js/main.********.js	425 kB
website/build/blog/2017/12/14/introducing-docusaurus/index.html	68.2 kB
website/build/blog/index.html	39 kB
website/build/docs/index.html	46.1 kB
website/build/docs/installation/index.html	53.6 kB
website/build/index.html	31.6 kB
website/build/tests/docs/index.html	27.3 kB
website/build/tests/docs/standalone/index.html	23.8 kB

_{compressed-size-action}

[slorber]

😓 Crowdin also unzip zipped files on upload, so using a .xslx instead