Serialization roundtrip corrupts `URI`

I noticed that `URI` were breaking after performing a serialization roundtrip.

Here is a MWE:

```
using URIs
using Serialization

uri = URI(; path = "some/relative/path.pdf", scheme = "file") # URI("file:some/relative/path.pdf")

buf = IOBuffer()
serialize(buf, uri)
seekstart(buf)
uri2 = deserialize(buf) # "URI("file://@:some/relative/path.pdf?#")
```

Perhaps the serialization should just go through string conversion and parsing?

Reproduce the issue with the Julia MWE using URIs and Serialization, then inspect the URI serialization and deserialization paths. Done means serializing and deserializing the relative file URI preserves its original value and does not add the observed authority, query, or fragment components.

Written by the indexing model from the issue text.