message: Add deepmerge as a dependency
diff: "@types/styled-system__css": "5.0.14",
  "@types/styled-system__theme-get": "5.0.1",
  "classnames": "^2.2.5",
  + "deepmerge": "4.2.2",
  "polished": "3.5.2",
  "react-is": "16.10.2",
  "styled-system": "5.1.2"
  "chroma-js": "2.1.0",
  "concurrently": "5.3.0",
  "cross-env": "7.0.2",
  - "deepmerge": "4.2.2",
  "enzyme": "3.10.0",
  "eslint": "6.5.1",
  "eslint-plugin-github": "4.1.1",
  