Remove options argument from tree()

[vmx]

With merging #38 there is no longer an options argument for tree(). Hence that should be removed from all format implementations to avoid confusion.

A replacement for the previously existing tree options is passing in the root / into resolve(), which is tracked by #34.

I suggest waiting for #34 to be finished, before working on this issue.

Instead of opening an issue on every repository, just let people know on this issue that you're working on it and then link to the PR.

• https://github.com/ipld/js-ipld-bitcoin
• https://github.com/ipld/js-ipld-dag-cbor
• https://github.com/ipld/js-ipld-dag-pb
• https://github.com/ipld/js-ipld-ethereum
• https://github.com/ipld/js-ipld-git
• https://github.com/ipld/js-ipld-raw
• https://github.com/ipld/js-ipld-zcash