Fixes for webpack 5 support (backward compatible)

[neilime]

What did you implement:

Webpack 5 removes deprecated functions, and add some minor changes that broke up this plugin

How did you implement it:

• Uses modulesIterable instead of forEachModule (already deprecated in version 4)
• Iterate over chunks with for ... of because stats.compilation.chunks is a Set now

How can we verify it:

Install webpack 5
run sls package

An error occured : Cannot read property 'forEachModule' of undefined

Todos:

• Write tests
• Write documentation
• Fix linting errors
• Make sure code coverage hasn't dropped
• Provide verification config / commands / resources
• Enable "Allow edits from maintainers" for this PR
• Update the messages below

Is this ready for review?: YES
Is it a breaking change?: NO

[HyperBrain]

@serverless-heaven/serverless-webpack-contributors Can anyone of you confirm, that this PR continues to work with old webpack versions?

[hassankhan]

@HyperBrain just tested it on my projects using Webpack v4.x, all seems to be working fine.

[hassankhan]

Code all looks good, getting a few lint errors on the branch. Aside from that, LGTM 👍

[HyperBrain]

@hassankhan Hmmm. It seems that Travis is not working any longer for the project. I'll check. We should get it running again, as it also checks for linter errors and blocks merges. Found the issue and reset the project settings

[HyperBrain]

@neilime Travis now works again - and stopped at the linter issues. Could you please address the issues?

[neilime]

@HyperBrain, it's done.

[hassankhan]

Hi @neilime, thanks for fixing the lint issues. Unfortunately, it seems test coverage has decreased (as noted by the failed coverage/coveralls check, would you mind having a quick look at those too?

[neilime]

@hassankhan, it's done.

[neilime]

You're right @hassankhan, I have change the code

[HyperBrain]

Released with 5.3.0