Clean up some files from dist version

Author: williamdes

.gitattributes

@@ -6,3 +6,7 @@
 /.travis.yml export-ignore
 /example.php export-ignore
 /phpunit.xml.dist export-ignore
+/.github export-ignore
+/.php_cs.dist export-ignore
+/phpstan.neon export-ignore
+/.coveralls.yml export-ignore