feat: Add webpack 5 support

Co-authored-by: Putzi San <putzisan@putzisan.de>
Co-authored-by: Øyvind Saltvik <oyvind.saltvik@gmail.com>

Author: 3 people

.travis.yml

@@ -3,9 +3,17 @@ node_js:
   - stable
   - lts/*
   - 6.9
+env:
+  - WEBPACK_CORE=4
+  - WEBPACK_CORE=beta
+jobs:
+  exclude:
+  - node_js: 6.9
+    env: WEBPACK_CORE=beta
 before_install:
   - stty columns 120
 install:
   - travis_retry npm install --ignore-scripts
+  - travis_retry npm install "webpack@$WEBPACK_CORE" --ignore-scripts
 script:
   - travis_retry npm test