Features

add experiments.layers
- entry.xxx.layer: "name-of-layer" allows to set the layer for an entrypoint
- module.rules[].issuerLayer: RuleCondition allows to filter/match by layer of issuer
- module.rules[].layer: "name-of-layer" allows to set the layer of an module
- splitChunks.cacheGroups.xxx.layer allows to select modules by layer
- externals.byLayer["name-of-layer"] allows to specify externals by layer
- externals.byLayer: (layer) => ... allows to specify externals by layer
- externals function has an additional argument property contextInfo which contains info about the issuer (e. g. the layer)
add module.parser and module.generator options to allow to specify parser/generator options globally per module type
make chunkId variable available in script tag hook (like it was with webpack 4)

Bugfixes

escape exclamation marks in context regexp when generating readable module names/ids
fix a problem when bundling webpack bundles with enabled eval-based devtools
add stats.nestedModulesSpace to schema to allow to specify this option
fix a bug that incorrectly replaces new.target with constants
fix a bug where splitChunk minSize is not handled correctly
fix a bug where the order of splitChunk cacheGroups is not handled correctly
avoid adding non-filesystem resources as dependencies for watching and caching

fix incorrect negation in hint comment for eval-based devtools
improve error messages of "Library/Chunk Loading/Wasm Loading typeof is not enabled" errors
improve question message when asking to install webpack-cli
show a warning when loaders/plugins report invalid dependencies to webpack