Fix build command to be cross-platform compatible

.github/workflows/build.yml

@@ -25,7 +25,7 @@ jobs:
                   npm ci
                   npm test --if-present
                   npm run lint
-                  npm run build 
+                  npm run build # TODO: build contains 'cp' which is unix based, so this will fail on windows [npm install --save-dev shx]
               env:
                   CI: true