Feature/allow custom runtime

[MatteoGioioso]

What did you implement:

Closes #664

Allow custom runtime if Nodejs based.

How did you implement it:

Those are the proposed changes:

We add an additional property to allow a custom runtime only if the user sets this to true

  exampleFunction:
    memorySize: 1024
    timeout: 30
    handler: services/myService/handler.default
    runtime: provided
    allowCustomRuntime: true

And then add another check:

if (runtime === 'provided' && loadedFunc.allowCustomRuntime) {
        const entry = getEntryForFunction.call(this, functions[index], loadedFunc);
        _.merge(entries, entry);
}

How can we verify it:

You can check this repository https://github.com/MatteoGioioso/serverless-webpack-bug

Without this feature

• Input: specify runtime: provided and use the latest version of serverless-webpack
• Output: serverless-webpack will skip anything that is not a nodejs runtime:

  serverless-webpack/lib/validate.js

  Line 104 in 69dfc3f

  if (runtime.match(/node/)) {

  
  Therefore it will package the entire project. You can inspect the .serverless folder after the packaging has completed

With this feature

• Input: specify runtime: provided and allowCustomRuntime: true with the version of this branch
• Output: this time it will allow a custom runtime, but only if the user explicitly allow it: https://github.com/MatteoGioioso/serverless-webpack/blob/b9941bb9f3d4e9772113e6621087e1ac607a77a2/lib/validate.js#L111
  The function will be packaged like normally. You can inspect the result in the .serverless folder after the packaging has completed

I have added a test as well to check this condition and updated the documentation.

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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

[j0k3r]

This looks ok, thanks @MatteoGioioso!

[MatteoGioioso]

@j0k3r cool thanks, I will wait for the release.