Update peerDependencies to support webpack@^5.0.0 for webpack-dev-middleware@^3.7.2

[hiwangyi]

Feature Proposal

Add webpack@^5.0.0 as a valid peer dependency for webpack-dev-middleware@^3.7.2

Feature Use Case

webpack-dev-middleware started to support webpack@5 from v3.7.2. Actually, the peerDependencies in package.json of v3.7.2 only contains webpack@^4.0.0.
webpack-dev-middleware@^3.7.2 is the dependency of webpack-dev-server@3.11.0. If webpack@5 and webpack-dev-server@3.11.0 are used at the same time, a warning message will be thrown when installing the dependencies:

warning "webpack-dev-server > webpack-dev-middleware@3.7.2" has incorrect peer dependency "webpack@^4.0.0".

[alexander-akait]

Please try https://github.com/webpack/webpack-dev-middleware/releases/tag/v3.7.3