Arguments are not passed to npm start script

[isibeni]

When running a container with additional args those are ignored and not consumed by this buildpack

Expected Behavior

If an container is invoked with arguments I would expect that those are passed onto the start script.

Similar as it's today possible to pass in args when run npm run or npm start like this: npm start [-- <args>] .
When using the node-start buildpack it's also possible to pass in arguments

Current Behaviour

Arguments are ignored and not passed to the running process and can therefore not be consumed at all.

Possible Solution

Ensure that the start.sh is passing the argument to the start script. So when building the args in builder.go we would need to add an $@ for the start script to ensure it will be able to consume arguments

Steps to Reproduce

1. Run a container build with this buildpack and pass in arguments.
2. Within the started process log all arguments

Motivations

We are having a usecase where one builts an application with this buildpack and wants to start it with different configuration using arguments.

[c0d1ngm0nk3y]

Note: The start.sh calls PreStart, Start and PostStart and we can just add $@ to the Start command.