fix(package.json): build-export script (#148)

### Related Ticket(s)

none 
### Description

build failing without setting `SASS_PATH=node_modules:src`. Updated it to be the same as  just the `build` script

Author: ariellalgilmore

package.json

@@ -17,7 +17,7 @@
     "build": "cross-env SASS_PATH=node_modules:src next build",
     "export": "next export",
     "start": "node server.js",
-    "build-export": "next build && next export",
+    "build-export": "cross-env SASS_PATH=node_modules:src next build && next export",
     "lint": "eslint pages",
     "lint:styles": "stylelint '**/*.{css,scss}' --config ./packages/stylelint-config-ibmdotcom",
     "prepare": "husky install",