[ BUG ] TypeError item.priority.toFixed not a function

[rafawashere]

Describe the bug
item.priority.ToFixed is throwing a TypeError in /dist/lib/sitemap-item-stream.js

Expected behavior
The item.priority is type is unknown and is trying to add to a number type.

Context:

• Library Version [e.g. 3.2.2]

Additional context
In my local version, I was able to resolve the issue by placing a primitive wrapper object.
item.priority.toFixed(1) => Number(item.priority).toFixed(1)