* feat: ledger support
Adds support for Ledger Nano S Eth app (v1.3.7)
- sign message
- sign transaction
- get addresses
- get app version
* fix: fix eth docstring
* fix: take into account EIP155
* feat: convert Signer to async
* feat: implement Signer for Ledger
* ci: run celo-only tests explicitly
This is done to avoid using --all-features
* fix: remove async from with_signer
* chore: fix doctests
* fix: add Send/Sync to SignerError
* ci: update etherscan key
* test: disable etherscan abigen tests temporarily
Georgios Konstantopoulos