added testes export-ignore to gitattributes

Author: leongrdic

.gitattributes

@@ -1,10 +1,7 @@
-# Path-based git attributes
-# https://www.kernel.org/pub/software/scm/git/docs/gitattributes.html
-
-# Ignore all test and documentation with "export-ignore".
 /.github            export-ignore
 /.gitattributes     export-ignore
 /.gitignore         export-ignore
 /.editorconfig      export-ignore
 /.php_cs.dist.php   export-ignore
 /phpunit.xml.dist   export-ignore
+/tests              export-ignore