Calcite CSS missing from "docs"

[nwhittaker]

Following the first grunt build, the docs site is unstyled. It becomes styled after subsequent builds (without cleaning in between).

Steps to reproduce

1. Clean check out (or run grunt clean and manually remove the docs/build directory).
2. Run grunt and visit http://0.0.0.0:8888.

Observed behavior

http://0.0.0.0:8888 is unstyled and ... "GET /assets/css/calcite-bootstrap.css" Error (404): "Not found" appears in the server log.

Expected behavior

http://0.0.0.0:8888 is styled similarly to http://esri.github.io/calcite-bootstrap/.

Fix

The issue appears to stem from a concurrency issue where the copy build step occurs before the scss step completes[1].

[1] https://github.com/Esri/calcite-bootstrap/blob/master/gruntfile.js#L365