Fix: add version for abci_info endpoint

[DavidVentura]

This PR adds the missing version field on ResponseInfo for the /abci_info endpoint.

This field (version) is useful for monitoring that all nodes are running the same version, which helps with automatic upgrades.

The new abci_info endpoint looks like this:

{
  "jsonrpc": "2.0",
  "id": "",
  "result": {
    "response": {
      "data": "Heimdall",
      "version": "1.2.3",
      "last_block_height": "34",
      "last_block_app_hash": "HhAiY2ecdj/P1JWPXFReNJDn8TLxWaKyJL3o3nAolVQ="
    }
  }
}