docs: update README.md links

[yapyuyou]

Relative links are causing an issue with the OA docs website when trying to build.

Error: Unable to build website for locale en.
    at tryToBuildLocale (/Users/lucasyap/Desktop/documentation-website/node_modules/@docusaurus/core/lib/commands/build.js:55:19)
    at async mapAsyncSequential (/Users/lucasyap/Desktop/documentation-website/node_modules/@docusaurus/utils/lib/jsUtils.js:44:24)
    at async Command.build (/Users/lucasyap/Desktop/documentation-website/node_modules/@docusaurus/core/lib/commands/build.js:82:21) {
  [cause]: Error: Docusaurus found broken links!
  
  Please check the pages of your site in the list below, and make sure you don't reference any path that does not exist.
  Note: it's possible to ignore broken links with the 'onBrokenLinks' Docusaurus configuration, and let the build pass.
  
  Exhaustive list of all broken links found:
  
  - On source page path = /docs/lib-section/remote-files/document-store:
     -> linking to src/interfaces/IDocumentStoreBatchable.sol (resolved as: /docs/lib-section/remote-files/src/interfaces/IDocumentStoreBatchable.sol)
     -> linking to src/interfaces/ITransferableDocumentStore.sol (resolved as: /docs/lib-section/remote-files/src/interfaces/ITransferableDocumentStore.sol)
     -> linking to foundry.toml#L28 (resolved as: /docs/lib-section/remote-files/foundry.toml)
     -> linking to .env.sample (resolved as: /docs/lib-section/remote-files/.env.sample)

[github-actions]

🎉 This PR is included in version 4.1.0 🎉

The release is available on:

• v4.1.0
• GitHub release

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