fix: Reduce vulnerabilities in packages/@css-blocks/website.

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-JSYAML-173999

Closes #239.

Author: chriseppstein

packages/@css-blocks/website/package.json

@@ -17,7 +17,7 @@
     "babel-runtime": "6.26.0",
     "case-sensitive-paths-webpack-plugin": "2.1.1",
     "chalk": "1.1.3",
-    "css-loader": "0.28.7",
+    "css-loader": "1.0.0",
     "dotenv": "4.0.0",
     "eslint": "4.10.0",
     "eslint-config-react-app": "^2.0.1",