Since 8.1.4 YAML.parseAllDocuments is not allowed from zx

### Expected Behavior
```js

```

### Actual Behavior
```js
TypeError: YAML.parseAllDocuments is not a function
```

### Steps to Reproduce

1. update zx to 8.1.4 
2. try to use YAML.parseAllDocuments(x)

### Specifications

- zx version:  8.1.4
- Platform: macos
- Runtime: node
