feat(fsa): decompress "json.gz" files automatically with readJson

[blacha]

Motivation

I have a number of files stored in s3 that are either Content-Encoding: gzip or .json.gz I would prefer not having to detect that they are Content-Encoding: gzip in all my scripts

Modification

readJson will now automatically decompress files ending with .gz

Before this would throw a error now it will return the object.

const obj = await fsa.readJson(new URL("s3://foo/bar.json.gz"))