ロングタームキャッシュ
参考：
Make use of long-term caching | Web Fundamentals | Google Developers [Official]
Predictable long term caching with Webpack – webpack – Medium
Caching Assets Long Term with Webpack – Connect the Dots – Medium
Long-term caching of static assets with Webpack – codeburst
Webpack 4 and Hashing for Long Term Caching – Stack Overflow
How to Cache? | Webpack (netlify.com)
ハッシュ生成
参考：
Avoid using webpack-md5-hash when using long-term caching – Anthony Ng – codeburst
recordsPath
参考：
Long term caching using Webpack records – Dennis Johnson – Medium