* [multistream-select] Fix panic with V1Lazy and add integration tests.
Fixes a panic when using the `V1Lazy` negotiation protocol,
a regression introduced in https://github.com/libp2p/rust-libp2p/pull/1484.
Thereby adds integration tests for a transport upgrade with both
`V1` and `V1Lazy` to the `multistream-select` crate to prevent
future regressions.
* Cleanup.
* Update changelog.