Support JSON-RPC 1.0

[hholst80]

Since the server should be stateless and its an request -> reply flow it would be reasonable that the server supported both JSON-RPC 1.0 and 2.0? Just ignore the "jsonrpc": "2.0" and maybe another schema validation (no support for batch, no support for object params). The server would need to track if it was a 1.0 or 2.0 request because the response will depend on that.

https://www.jsonrpc.org/specification_v1

[bcb]

This has been asked before in the client library (explodinglabs/jsonrpcclient#111). I still consider these libraries are implementations of the 2.0 spec. The 1.0 spec has been superceded since 2008 or something (not sure exactly). Do you need this or just think we should have it?