Upgrade material ui in react-docs

packages/react-docs/package.json

@@ -37,7 +37,7 @@
         "@0xproject/react-shared": "^1.0.8",
         "@0xproject/utils": "^1.0.7",
         "@types/lodash": "4.14.104",
-        "@types/material-ui": "0.18.0",
+        "@types/material-ui": "^0.20.0",
         "@types/node": "^8.0.53",
         "@types/react": "*",
         "@types/react-dom": "*",
@@ -45,7 +45,7 @@
         "basscss": "^8.0.3",
         "compare-versions": "^3.0.1",
         "lodash": "^4.17.5",
-        "material-ui": "^0.17.1",
+        "material-ui": "^0.20.0",
         "react": "^16.4.2",
         "react-dom": "^16.4.2",
         "react-markdown": "^3.2.2",