Use ipfs:// instead of fs://ipfs

[lidel]

Hi, this is a drive-by comment from IPFS 🚗 💨

The fs:/ was droped as an idea some years ago.
Since then we switched to ipfs://, ipns:// and dweb:/
See ipfs/in-web-browsers/ADDRESSING.md for up-to-date recommendations.

Would be fantastic to add archon support for ipfs:// and deprecate/remove fs:/ in code and docs.

[satello]

Will do. Thanks for the clarifications in ethereum/EIPs#1497 (comment). For the purposes of this library we will only be dealing with immutable files (at the moment). The preferred URI scheme I have been using is /ipfs/{cid}. I had support for fs:/ and ipfs:/ to try to cover all standard file formats, I will update to ipfs:// and dweb:/ instead

[jaybuidl]

Closing this. The current scheme is consistent with Protocol Lab's proposed Multiaddress scheme which appears superior to RFC3986 URIs.

Context: kleros/builder-baseline#16