Pin colorbrewer to 1.3.0.
Version 1.5.1 has changed how it is bundled, which no longer works with
out current examples.  Until that is refactored, pin to the last known
working version.
MODIFY
package.json
package.json
"bootswatch": "^3.4.1",
"bowser": "^1.9.4",
"codemirror": "^5.54.0",
- "colorbrewer": "^1.3.0",
+ "colorbrewer": "1.3.0",
"css-loader": "^0.28.11",
"docco": "^0.7.0",
"eslint": "^5.16.0",

Pin colorbrewer to 1.3.0.

Version 1.5.1 has changed how it is bundled, which no longer works with
out current examples.  Until that is refactored, pin to the last known
working version.