Incorrect array schema in eth_getWork

[lightclient]

From @conradev in #153:

I wrote something to parse openrpc.json and it failed to parse because items is an array, when it should be an object

prefixItems is an array of schemas, in order of the expected items in the array

It seems like this is an upstream issue with the OpenRPC tooling though.

[BelfordZ]

created an issue to track this json-schema-tools/meta-schema#175

[Dr-Electron]

Technically this could be closed now, no? #429

[BelfordZ]

Still intending to add support to json schemas for openrpc though - would happily take a PR if anyone wants to do it.