JSON RPC 2.0 request schema: add minItems to batch

[LinusU]

From spec:

If the batch rpc call itself fails to be recognized as an valid JSON or as an Array with at least one value, the response from the Server MUST be a single Response object.

...

rpc call with an empty Array:

--> []
<-- {"jsonrpc": "2.0", "error": {"code": -32600, "message": "Invalid Request"}, "id": null}

[LinusU]

ping @fge :)

[LinusU]

ping @fge, any chance of getting this merged?

[LinusU]

ping @fge, would love to get this merged :)

[LinusU]

yearly ping @fge 😄

[LinusU]

ping @fge :)