Spaces in the query string are encoded as `%20` instead of `+`

[balazsbotond]

Input:

urlcat('http://example.com', '/path', { q: 'a b' })

Expected:

http://example.com/path?q=a+b

Actual:

http://example.com/path?a%20b

[flxwu]

Hey,

so actually in some use cases (like OAuth1) we require whitespaces to be encoded as %20, instead of +.

Can you thus please add an option to encode it as %20?

Thanks :)