feat!: Remove simple::SimpleProtocol

[mxinden]

Description

Due to lack of usage, remove the simple::SimpleProtocol. Users may look at libp2p::core::upgrade for alternatives.

Notes

Discovered through @umgefahren's master docs (#3126).

Links to any relevant issues

Open Questions

• @thomaseizinger what would be the right conventional commit prefix here?

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• A changelog entry has been made in the appropriate crates

[jxs]

LGTM

[thomaseizinger]

@thomaseizinger what would be the right conventional commit prefix here?

Uhm, good question. This discussion discussion suggests refactor! or feat!. Personally I tend towards feat! because refactoring something shouldn't change the feature set.

[mxinden]

Testground failure is due to a rename:

failed to load composition file: failed to process composition template: open ping/_compositions/go-rust-interop-latest.toml: no such file or directory

libp2p/test-plans#70

See #2647 (comment) for libp2p-relay and libp2p-dcutr failures.

[thomaseizinger]

Testground failure is due to a rename:

failed to load composition file: failed to process composition template: open ping/_compositions/go-rust-interop-latest.toml: no such file or directory

libp2p/test-plans#70

Fix is here: #3203

[mergify]

This pull request has merge conflicts. Could you please resolve them @mxinden? 🙏

[mxinden]

For libp2p-dcutr and libp2p-relay failure, see #2647 (comment).