Document webpack change: add `experiments.buildHttp`

[webpack-bot]

A pull request by @sokra was merged and maintainers requested a documentation change.

See pull request: webpack/webpack#13925

---

• allows to build remote resources from the http(s): protocol
• During development:
  • creates and updates a lockfile <name>.webpack.lock
    • This file is expected to be committed to version control
  • persists remote resource contents in <name>.webpack.lock.data/**
    • It's possible to disable that with cacheLocation: false
    • These files are expected to be committed to version control
  • changes to remote resources are detected and the lockfile resp. content is updated automatically
    • It's possible to opt-out of automatic updating via upgrade: false
  • In memory or persistent cache is used to cache resources based on Cache-Control header and make If-None-Match requests.
    • That will be used for upgrade requests or when cacheLocation: false
• During production it operates in frozen lockfile mode:
  • No network requests are made and build is done from lockfile and content
  • Missing or incorrect resources will lead to an error
• Cache-Control: no-cache resource are not cached, persistent or locked. They will be requested on each build.

Example: https://github.com/webpack/webpack/tree/feature/http-urls/examples/build-http

What kind of change does this PR introduce?
feature

Did you add tests for your changes?
yes

Does this PR introduce a breaking change?
no

What needs to be documented once your changes are merged?

• experiments.buildHttp: true
• experiments.buildHttp.frozen: boolean
• experiments.buildHttp.upgrade: boolean
• experiments.buildHttp.cacheLocation: string | false
• experiments.buildHttp.lockfileLocation: string

[samrun0]

Please update the readme file which doesn't work since it's required to be a regular expression similar to: https://github.com/webpack/webpack/blob/main/examples/build-http/webpack.config.js

The link has also changed: https://github.com/webpack/webpack/tree/main/examples/build-http