add .gitattributes to reduce package size/files

Author: Gummibeer

.gitattributes

@@ -0,0 +1,10 @@
+/.github                    export-ignore
+/tests                      export-ignore
+/.gitattributes             export-ignore
+/.gitignore                 export-ignore
+/.php-cs-fixer.dist.php     export-ignore
+/.php-cs-rules.laravel.php  export-ignore
+/.phpstorm.meta.php         export-ignore
+/phpunit.xml.dist           export-ignore
+/queries/.graphqlconfig     export-ignore
+/queries/github.json        export-ignore