Need to include all of the extra Composer files

Hopefully this fixes:

```
Warning: file_get_contents(phar:///tmp/wp-cli-phar/wp/vendor/composer/composer/src/Composer/Json/../../../res/composer-schema.json): failed to open stream: phar error: "vendor/composer/composer/res/composer-schema.json" is not a file in phar "/tmp/wp-cli-phar/wp" in phar:///tmp/wp-cli-phar/wp/vendor/composer/composer/src/Composer/Json/JsonFile.php on line 153
```