[bug] incompatible Date type between JSON & YAML

[TechQuery]

What happened?

Resume data

work:
    - startDate: 2020-01-23

isn't equal to

{
    "work": [
        { "startDate": "2020-01-23" }
    ]
}
So, some themes will crash with:

```Shell
resume export --resume resume.yml

My environment

• resume-cli: 3.0.3
• Node.js: 14.15.0

[michaeltlombardi]

In my experience/testing, this also breaks resume validate calls in v3.0.5