Support go1.20

[Jorropo]

This is currently blocked due to this regression golang/go#60674

[lidel]

Triage notes:

• we need to find a way to fix multipart on /api/v0 RPC (ideally, backward-compatible, if not, we need to make patch releases for all RPC client libraries) @hacdias

[aschmahmann]

Note: this feels an awful lot like #8445 and ipfs/go-ipfs-files#42 (i.e. Go broke compatibility somewhere in the mimetype land, so we copy-paste code out of Go so we don't get forced to spend time on dealing with the breakages from this specific API on the Go team's schedule)

[hacdias]

@aschmahmann the thing is that in ipfs/go-ipfs-files#42 it was just a few lines. Here it would be much more. We'd need the whole multipart reader, as well as copying the functions to convert an http.Response body to a multipart reader.

I think the path forward is to percent encode the names and make a patch release to the RPC client libraries (cc @Jorropo @lidel as this was discussed during triage).

[Jorropo]

I agree with %-encoding it, this is gonna break binary file paths with older clients but updating to a newer client will bring the feature back.