chore(git): Introduce .gitattributes file

Signed-off-by: Plakhotnikov Vladimir <v.plahotnikov@yclients.tech>

.gitattributes

@@ -0,0 +1,20 @@
+* text=auto eol=lf
+
+/.github export-ignore
+/tests export-ignore
+/.cz.json export-ignore
+/.ecrc export-ignore
+/.envrc export-ignore
+/.fossa.yaml export-ignore
+/.gitattributes export-ignore
+/.editorconfig export-ignore
+/.gitignore export-ignore
+/.markdownlint.json export-ignore
+/.php-cs-fixer.dist.php export-ignore
+/composer-require-checker.json export-ignore
+/CONTRIBUTING.md export-ignore
+/flake.lock export-ignore
+/flake.nix export-ignore
+/phpstan.neon export-ignore
+/phpstan-baseline.neon export-ignore
+/phpunit.xml.dist export-ignore