Use file's created time to print build error message

[fadedimon]

updatedAt property in builded lists breaks bundle caching and messing up with "identical build checks"

This PR implements @jhnns solution to use created file time

Based on this issue: #60

[jhnns]

We can't use the birthdate because that will be the date when npm install has been executed. We just need to save the date in separate file. I'm going to implement that :)

Anyway, thanks 👍

[jhnns]

Follow up #75

[fadedimon]

@jhnns Since separate file contains data based on it's generated time, problem is still here: we still have not matching files at every build :)

Maybe we can use last-modified time and not created-time?

[jhnns]

Since separate file contains data based on it's generated time, problem is still here: we still have not matching files at every build :)

I don't get the problem :). The meta.json is not included in a bundle because it is not imported/required anywhere.