Feature/meditor 829 codepipeline

[benforshey]

This PR adds two features related to our AWS Deployment Pipeline:

1. adds a bash script to get the root package.json's version for use in CodeBuild
2. adds ARG to the two Dockerfiles that didn't have it; we pull images from ECR when building with Docker to prevent a 429 response

[KrupaRami]

Are we all agreed to use this file to keep record of updates in each versions? I know there were conversations for using Changelog file. Just wanted to make sure :)

[benforshey]

@joncarlson Any thoughts on manual changelogs, automated changelogs, checklists, etc (from our other PR conversation)?

[joncarlson]

My one reservation about changelogs is that historically they have not been kept up to date, which is why we haven't implemented them in mEditor.

So the question is, if we start adding changelogs, how do we ensure they stay updated? Having a checklist, or even better, a merge check, would go along way to making sure the changelog is actually useful

[benforshey]

Agreed that a checklist / merge check seems like a really good way to remind people to update tests and documentation. I'd fully support that for all our repos, so I'll make a note to discuss this on Thursday.

[joncarlson]

This is awesome, so much better than running shell scripts locally!