message: Update obsolete URLs in Readme
diff: @@ -15,11 +15,11 @@ The Casper MainNet is live.
  ## Specification
  -- [Platform Specification](https://docs.casperlabs.io/en/latest/implementation/index.html)
  +- [Platform Specification](https://docs.casperlabs.io/design/)
  - [Highway Consensus Proofs](https://github.com/CasperLabs/highway/releases/latest)
  ## Get Started with Smart Contracts
  -- [Writing Smart Contracts](https://docs.casperlabs.io/en/latest/dapp-dev-guide/index.html)
  +- [Writing Smart Contracts](https://docs.casperlabs.io/dapp-dev-guide/)
  - [Rust Smart Contract SDK](https://crates.io/crates/cargo-casper)
  - [Rust Smart Contract API Docs](https://docs.rs/casper-contract/latest/casper_contract/contract_api/index.html)
  - [AssemblyScript Smart Contract API](https://www.npmjs.com/package/casper-contract)
  