Add .gitattributes file

[ker0x]

Description
I would like to suggest adding a .gitattributes file to avoid fetching unnecessary folders and files when installing the package via composer.

WDYT?

Basic example

# Path-based git attributes
# https://www.kernel.org/pub/software/scm/git/docs/gitattributes.html

/.github                            export-ignore
/tests                              export-ignore
/.code-samples.meilisearch.yaml     export-ignore
/.gitattributes                     export-ignore
/.gitignore                         export-ignore
/.php-cs-fixer.dist.php             export-ignore
/bors.toml                          export-ignore
/docker-compose.yml                 export-ignore
/docker-entrypoint.sh               export-ignore
/Dockerfile                         export-ignore
/phpstan.neon                       export-ignore
/phpunit.xml.dist                   export-ignore

[brunoocasali]

Hi @ker0x feel free to go ahead and submit the PR 🥇