feat(webpack-cli): allow multiple entry files

[snitin315]

What kind of change does this PR introduce?
Feature

Did you add tests for your changes?
YES
If relevant, did you update the documentation?
YES
Summary
Now we can provide multiple entry files via CLI using -

• webpack --entry=a.js --entry=b.js
• webpack ./a.js ./b.js

Refers #717
Fixes #1454

Does this PR introduce a breaking change?

Other information

[alexander-akait]

We should not implement --multiple-flag, we should allow to run

webpack src/one.js src/two.js src/three.js

[snitin315]

webpack src/one.js src/two.js src/three.js

@evilebottnawi we can do this for entry but what about other flags that can take multiple values?

[alexander-akait]

@snitin315 Let's start with entry, it is most popular use case

[snitin315]

Ready for review 🙌

[snitin315]

/cc @anshumanv @rishabh3112 @jamesgeorge007

[alexander-akait]

/cc @webpack/cli-team

[alexander-akait]

/cc @rishabh3112

[webpack-bot]

@anshumanv Thanks for your update.

I labeled the Pull Request so reviewers will review it again.

@rishabh3112 Please review the new changes.

[octaharon]

Hey lads. What about named entries? Webpack 4 allowed passing <name>=<request> as entry, as of now it doesn't seem to work, and "--entry" argument is treated like a filepath regardless of format. There seems to be no deprecation warning about it, will this functionality be restored?

[petemill]

Hey lads. What about named entries? Webpack 4 allowed passing = as entry, as of now it doesn't seem to work, and "--entry" argument is treated like a filepath regardless of format. There seems to be no deprecation warning about it, will this functionality be restored?

Confirming this is broken now in webpack-cli. You cannot define an entry's name in the cli, preventing different compiled file names than entry file names, where this is possible in webpack config.