v1.9.1

• Breaking change (TypeScript with derives only) The return type names for api.derive.* have been adjusted for consistency, all starting with Derive* (previously a mixture of Derived* and Derive*)
• Breaking change (derives only) Additional cleanups of democracy proposal & referenda derives, including support for new Polkadot/Substrate vote retrievals
• Tx signing via signAndSend & signAsync now tries to use the last finalized block (depending on finalized drift)
• Add support for api.rpc.childstate.* Substrate RPCs, older nodes with still populate api.rpc.state.* with the child methods
• Adjust Error.message on RPC failures to not include the (already known) method signature
• Split @polkadot/types/known into @polkadot/types-known, allowing for base API overrides
• Extended api.derive.democracy to cater for dispatchQueue and externals
• Extended api.derive.council to cater for new phragmen elections
• Use new queryStorageAt for query .entries, removing unneeded subscriptions (use as available)
• Fix BTreeSet initialization when it forms part of query interfaces
• Fix encoding for Vec<u8>-related types as part of constants
• Internal adjustment of interface type locations (no impact on imports via @polkadot/types/interfaces)