SG721 Contract v0.8.0

Stargaze's NFT contract sg721 is a set of optional extensions on top of cw721-base, and conforms to the cw721 specification.\n\nSource Code:\nhttps://github.com/public-awesome/stargaze-contracts/tree/v0.8.0/contracts\n\n\n\n## Verifiying Contracts\n\n# download the contract from the proposal\nstarsd q gov proposal [proposal-number] -o json | jq -r .content.wasm_byte_code | base64 --decode > sg721.wasm.gz\n\n# decompress de contract\ngzip -d -c sg721.wasm.gz > sg721.wasm \n\n# checksum\nsha256sum sg721.wasm\n\n\n# clone the repo and checkout to the release\ngit clone https://github.com/public-awesome/stargaze-contracts.git\ncd stargaze-contracts\ngit checkout v0.8.0\n\n\n# compile and optimize contracts\ndocker run --rm -v "$(pwd)":/code \\n --mount type=volume,source="$(basename "$(pwd)")_cache",target=/code/target \\n --mount type=volume,source=registry_cache,target=/usr/local/cargo/registry \\n cosmwasm/workspace-optimizer:0.12.5\n\n\n# checksum \nsha256sum artifacts/sg721.wasm\n