Description

Resolves #4072. The task make-tmp-directory in release.js was being started before build task was finished. This resulted in incomplete ZIP files of release builds.

• Modifies tasks insvg-sprite.js so the streams are returned after they finish
• Adds svg-sprite as parallel task

Additional information

Steps to test:

• Pull branch
• Run npx gulp release
• Verify contents of ZIP file, specifically scss/utilities/palettes as well as img/ and img/usa-icons
  Previously, builds looked successful but img directory would be empty or more nested SCSS folders would be empty. Aside from JS directory being missing.

Before you hit Submit, make sure you’ve done whichever of these applies to you:

• Follow the 18F Front End Coding Style Guide and Accessibility Guide.
• Run npm test and make sure the tests for the files you have changed have passed.
• Run your code through HTML_CodeSniffer and make sure it’s error free.
• Title your pull request using this format: [Website] - [UI component]: Brief statement describing what this pull request solves.