v8.6.1

Changes:

• Add codec support for specialized Option<bool>
• Optimization for createClass with shortcut typeDef creation
• Optimization of registry.getOrUnknown with lookup cache
• Optimization of Array allocations in decoding
• Use compactFromU8aLim & u8aConcatStrict variants
• Adjust .inspect() for ExtrinsicPayload
• Adjust Kusama StakingLedger for runtime 1051
• Update to latest Substrate, Kusama & Polkadot static metadata