Release v0.2.0

What's Changed

• Update types by @drewstone in #319
• Update CI's Nodejs to v18 by @shekohex in #320
• Update package.json by @drewstone in #321
• Update pallet-benchmarks to weights-v2 by @1xstj in #322
• add babel and create cjs build by @salman01zp in #324
• Add clippy check to CI by @1xstj in #323
• RPC call to check if given root is known root of merkle tree by @salman01zp in #327
• Update license year, fix comment, add more pallet docs by @drewstone in #328
• Add Nix flakes devenv by @shekohex in #329
• Add Circom stuff to the Runtime by @shekohex in #330

Full Changelog: v0.1.4...v0.2.0