Send valid JSON-RPC 2.0 requests

[jirijakes]

This PR adds jsonrpc member to all messages to comply with JSON-RPC 2.0 specification:

The Request object has the following members:
    jsonrpc: A String specifying the version of the JSON-RPC protocol. MUST be exactly "2.0".
    …

[mutatrum]

I'm not sure the Stratum API follows the json-rpc spec?

[jirijakes]

I'm not sure the Stratum API follows the json-rpc spec?

The widely linked specification at https://reference.cash/mining/stratum-protocol claims so. But I am not sure whether that is generally accepted or not.

[mutatrum]

I've never seen that one. Not claiming that it's not a valid source, but I only know https://en.bitcoin.it/wiki/Stratum_mining_protocol. I also don't know what in the new BIP-40/BIP-41 is proposed?

[jirijakes]

I only know https://en.bitcoin.it/wiki/Stratum_mining_protocol

Seems like the page behind "Original example on slush's pool site" link in this document also says JSON-RPC 2.0: https://web.archive.org/web/20150307191254/http://mining.bitcoin.cz/stratum-mining#developers

BIP40 (draft) says both JSON-RPC 1.0 and 2.0 are acceptable: https://github.com/ben221199/bips/blob/add-bip40/bip-0040.mediawiki#specification-data-format . But IIUC that is not for mining. I think BIP41 draft is not yet written.

[ben221199]

The BIP41 draft indeed is not written yet. I will then investigate if both JSON-RPC 1.0 or 2.0 are accepted.