Zebra 1.0.0-alpha.13

Zebra's latest alpha continues our work on NU5, including Orchard and Transaction V5. New validation
rules were implemented for transactions, preventing double spends in the Sprout pool, checking
Sapling spends in V5 transactions, and some initial work to validate parts of Orchard transactions.

Added

• Reject duplicate sprout nullifiers in the state (#2477)
• Add methods for getting block nullifiers (#2465)
• Verify orchard spend auth (#2442)
• Parse and ignore MSG_WTX inventory type in network messages (part of ZIP-239) (#2446)
• Add ZIP-244 signature hash support (#2165)
• Add HistoryTree struct (#2396)
• Add ZIP-0244 TxId Digest support (#2129)
• Validate V5 transactions with Sapling shielded data (#2437)

Documentation

• Document some consensus-critical finalized state behaviour (#2476)
• Value pools design (#2430)

Changed

• Move Utxo type to zebra-chain (#2481)
• Combine near-duplicate Utxo creation functions (#2467)

Documentation

• Update state RFC for incremental trees, value pools, and RocksDB (#2456)
• Modify UTXO and state designs for transparent coinbase output checks (#2413)

Fixed

• When a parent block is rejected, also reject its children (#2479)
• Restore the previous non-finalized chain if a block is invalid (#2478)
• Stop ignoring sapling binding signature errors (#2472)
• Always compute sighash with librustzcash (#2469)
• Fix bug in sighash calculation for coinbase transactions (#2459)
• Increase coverage of cached state tests: full block and transaction validation, and non-finalized state validation (#2463)