docs/node/network/testnet: Bump Sapphire to 1.3.0

Author: peternose

docs/node/network/testnet.md

@@ -66,7 +66,7 @@ This chapter contains parameters for various ParaTimes known to be deployed on t
 * Runtime identifier:
   * `000000000000000000000000000000000000000000000000a6d1e3ebf60dff6c`
 * Runtime bundle version:
-  * [1.2.0-testnet](https://github.com/oasisprotocol/sapphire-paratime/releases/tag/v1.2.0-testnet)
+  * [1.3.0-testnet](https://github.com/oasisprotocol/sapphire-paratime/releases/tag/v1.3.0-testnet)
 * Web3 Gateway version:
   * [5.3.4](https://github.com/oasisprotocol/oasis-web3-gateway/releases/tag/v5.3.4)