Update build process to use Webpack

.travis.yml

@@ -1,5 +1,5 @@
 language: node_js
-node_js: '10'
+node_js: '12'
 
 os:
   - linux
@@ -10,10 +10,6 @@ branches:
     - 'next'
 
 script:
-  - npm run build
-  # The `--no-cache` flag disables Parcel's cache as it can cause errors with building
-  # same entries targeting different destinations.
-  - npm run docs -- --no-cache
   - npm run lint
   - npm run test:unit
   - '[[ ! -z "$SAUCE_ACCESS_KEY" ]] && travis_wait npm run test:visual || true'
@@ -22,6 +18,10 @@ after_success:
   # Upload screenshots to Argos
   - '[[ ! -z "$ARGOS_TOKEN" ]] && argos upload test/screenshots/local -C $TRAVIS_COMMIT -B $TRAVIS_BRANCH -T $ARGOS_TOKEN || true'
 
+before_deploy:
+  - npm run build
+  - npm run docs
+
 deploy:
   - provider: script
     script: npx semantic-release