Compound.js v0.3.0

• Updated Ethers.js dependency to the latest version
• London hard fork updates - transaction request fixes
• All of the latest assets are available for mainnet functionality (as of prop 54)
• Newest mainnet Price Feed contract is integrated
• Legacy Price Feed assets were removed from the constants file (GRT, XTZ, KNC, SNX)

Available now on NPM: https://www.npmjs.com/package/@compound-finance/compound-js