Move to (at least) es2015

[SamMousa]

Are you requesting a feature, reporting a bug or ask a question?

Feature

What is the current behavior?

Compilation target is set to es5 which is ancient.

What is the expected behavior?

To be able to use Promises in PRs

How would you reproduce the current behavior (if this is a bug)?

Use a promise in any file in packages/survey-creatore-core

[tsv2013]

Could you please describe in more details - what to you want to implement in async/await style? We need to understand how it will affect other parts of our products.