* Update web3 dependency.

* Switch to crates.io.

Bumps [structopt](https://github.com/TeXitoi/structopt) from 0.3.14 to 0.3.15.
- [Release notes](https://github.com/TeXitoi/structopt/releases)
- [Changelog](https://github.com/TeXitoi/structopt/blob/master/CHANGELOG.md)
- [Commits](https://github.com/TeXitoi/structopt/compare/v0.3.14...v0.3.15

)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Bumps [derive_more](https://github.com/JelteF/derive_more) from 0.99.7 to 0.99.8.
- [Release notes](https://github.com/JelteF/derive_more/releases)
- [Changelog](https://github.com/JelteF/derive_more/blob/master/CHANGELOG.md)
- [Commits](https://github.com/JelteF/derive_more/compare/v0.99.7...v0.99.8

)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Bumps [async-trait](https://github.com/dtolnay/async-trait) from 0.1.35 to 0.1.36.
- [Release notes](https://github.com/dtolnay/async-trait/releases)
- [Commits](https://github.com/dtolnay/async-trait/compare/0.1.35...0.1.36

)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Bumps [serde](https://github.com/serde-rs/serde) from 1.0.112 to 1.0.114.
- [Release notes](https://github.com/serde-rs/serde/releases)
- [Commits](https://github.com/serde-rs/serde/compare/v1.0.112...v1.0.114

)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Bumps [parity-crypto](https://github.com/paritytech/parity-common) from 0.6.1 to 0.6.2.
- [Release notes](https://github.com/paritytech/parity-common/releases)
- [Commits](https://github.com/paritytech/parity-common/compare/parity-crypto-v0.6.1...parity-crypto-v0.6.2

)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Before the refactoring the sync loop would wait until a client finished
handling a request before issuing another one. This behaviour was
inadvertently changed during the refactoring leading to race conditions.
This commit makes sure that the previous behaviour is respected.

Svyatoslav Nikolsky authored Jun 18, 2020 and Hernando Castano committed Jun 18, 2020

Both Substrate and Ethereum's RPCs use positional (array) parameters,
so in order to be compatible with both we need to make sure that
our API is defined with positional paramters in mind.

* Error::TryingToFinalizeSibling

* cargo fmt --all

* updated PruningStrategy comment

Some of the RPCs that were "high level" didn't necessarily belong
as part of the trait, so they were removed.

By using a `jsonrpsee::Client` we are able to remove all the shared
mutable references required when interacting with the RPC server. This
is convenient as trying to sharing mutable references in code that uses
async/await is a bit of a pain.

However, using a `Client` instead of a `RawClient` is not yet supported
by the `jsonrpsee::rpc_api` macro, so a fork must be used for the moment.

* move pruning strategy to runtim level

* cargo fmt --all

* Update modules/ethereum/src/lib.rs

Co-authored-by: Hernando Castano <[email protected]>

* finalize_headers -> finalize_and_prune_headers

* PruningStrategy::default()

* fn import_of_non_best_block_may_finalize_blocks()

Co-authored-by: Hernando Castano <[email protected]>