message: Bump: `metamask` package version to `3.1.0`
diff: {
  "name": "@purser/metamask",
  - "version": "3.0.0",
  + "version": "3.1.0",
  "description": "A javascript library to interact with a Metamask based Ethereum wallet",
  "license": "MIT",
  "main": "lib/index.js",
  