## Issue Addressed
Upgrade libp2p to v0.52
## Proposed Changes
- **Workflows**: remove installation of `protoc`
- **Book**: remove installation of `protoc`
- **`Dockerfile`s and `cross`**: remove custom base `Dockerfile` for cross since it's no longer needed. Remove `protoc` from remaining `Dockerfiles`s
- **Upgrade `discv5` to `v0.3.1`:** we have some cool stuff in there: no longer needs `protoc` and faster ip updates on cold start
- **Upgrade `prometheus` to `0.21.0`**, now it no longer needs encoding checks
- **things that look like refactors:** bunch of api types were renamed and need to be accessed in a different (clearer) way
- **Lighthouse network**
- connection limits is now a behaviour
- banned peers no longer exist on the swarm level, but at the behaviour level
- `connection_event_buffer_size` now is handled per connection with a buffer size of 4
- `mplex` is deprecated and was removed
- rpc handler now logs the peer to which it belongs
## Additional Info
Tried to keep as much behaviour unchanged as possible. However, there is a great deal of improvements we can do _after_ this upgrade:
- Smart connection limits: Connection limits have been checked only based on numbers, we can now use information about the incoming peer to decide if we want it
- More powerful peer management: Dial attempts from other behaviours can be rejected early
- Incoming connections can be rejected early
- Banning can be returned exclusively to the peer management: We should not get connections to banned peers anymore making use of this
- TCP Nat updates: We might be able to take advantage of confirmed external addresses to check out tcp ports/ips
Co-authored-by: Age Manning <Age@AgeManning.com>
Co-authored-by: Akihito Nakano <sora.akatsuki@gmail.com>
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