build(deps): bump jsonrpc-core from 14.0.5 to 14.2.0

Bumps [jsonrpc-core](https://github.com/paritytech/jsonrpc) from 14.0.5 to 14.2.0.
- [Release notes](https://github.com/paritytech/jsonrpc/releases)
- [Commits](paritytech/jsonrpc@jsonrpc-core-v14.0.5...v14.2.0)

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

Author: dependabot-preview[bot]

Cargo.lock

@@ -7,7 +7,7 @@ edition = "2018"
 chrono = "0.4"
 failure = "0.1.7"
 futures = "0.1.21"
-jsonrpc-core = "14.0.5"
+jsonrpc-core = "14.2.0"
 graph = { path = "../../graph" }
 mock = { package = "graph-mock", path = "../../mock" }
 lazy_static = "1.2.0"