Migration to ibc_proto v.0.3.0

[ancazamfir]

Closes: #226

Description

Migrate to ibc_proto v0.3.0.

Includes minimal changes such that the code compiles and tests pass. In particular:

• the client state in the handshake messages is not deserialized and therefore further ignored
• the epoch in the new type Height is ignored and the deserialization code only extracts the EpochHeight in the current Height type which is u64.

---

For contributor use:

• Unit tests written
• Added test to CI if applicable
• Updated CHANGELOG_PENDING.md
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Updated relevant documentation (docs/) and code comments
• Re-reviewed Files changed in the Github PR explorer

[romac]

Looks good, modulo some typos and a couple idioms :) Will leave it to @adizere to approve the PR as I am not super familiar with ICS 03 yet.

[adizere]

Heads-up, once we merge #220 we might get the following error:

$ cargo clippy --all-targets
    Checking ibc v0.0.3 (/Users/adi/Hammers/ibc-rs/modules)
error: large size difference between variants
  --> modules/src/ics03_connection/msgs.rs:51:5
   |
51 |     ConnectionOpenTry(MsgConnectionOpenTry),
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this variant is 352 bytes
   |
note: the lint level is defined here
  --> modules/src/lib.rs:2:9
   |
2  | #![deny(clippy::all)]
   |         ^^^^^^^^^^^
   = note: `#[deny(clippy::large_enum_variant)]` implied by `#[deny(clippy::all)]`
note: and the second-largest variant is 144 bytes:
  --> modules/src/ics03_connection/msgs.rs:50:5
   |
50 |     ConnectionOpenInit(MsgConnectionOpenInit),
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#large_enum_variant
help: consider boxing the large fields to reduce the total size of the enum
   |
51 |     ConnectionOpenTry(Box<MsgConnectionOpenTry>),
   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

error: could not compile `ibc`.```

[adizere]

I think clippy will bite us with next commits, so we'll need to address that (see my earlier comment). Otherwise looks good!

[ancazamfir]

Another need to fix before merge:

When running the Rust relayer query with Gaia and Go Relayer, the connection query fails.

cargo run --bin relayer -- -c simple_config.toml query connection end ibc0 ibconeconnection
    Finished dev [unoptimized + debuginfo] target(s) in 0.14s
     Running `target/debug/relayer -c simple_config.toml query connection end ibc0 ibconeconnection`
     Options QueryConnectionOptions { connection_id: ConnectionId("ibconeconnection"), height: 0, proof: true }
[relayer/src/chain/cosmos.rs:67] "Todo: implement proof verification." = "Todo: implement proof verification."
connection query error Could not parse/unmarshall response: failed to decode Protobuf message: ConnectionEnd.state: invalid wire type: LengthDelimited (expected Varint)

The failure is here:
https://github.com/informalsystems/ibc-rs/blob/6f59e2f047777e881fdff79cb8181ed30f76c733/relayer/src/chain/cosmos.rs#L72

The query works on master (with ibc-proto v.0.1.0), the protobuf for ConnectionEnd hasn't changed between the two versions.

The channel query that gets a ChannelEnd with an almost identical proto for Sate works fine.