Should parse json string flag

[SamProtas]

Description of change

As discussed #92

This allows users to opt-out of the metafield.value "parse json_string" behavior. I needed this because my desired target (singer-target-postgres) did not support a single field being int/string/object.

The Shopify API returns a string field, this feature lets the user keep it a string.

QA steps

• automated tests passing
• manual qa steps passing (list below)

I've been running this locally against our live Shopify store. I've observed it correctly working (keeping metafield.value as a string type when metafield.value_type is json_string). I've observed this allowing this shopify value to end up in my postgres db via singer-target-postgres, solving my problem.

Risks

This adds a small amount of surface area to the code, but this doesn't appear to interact with anything else in the program.

Rollback steps

• revert this branch

[cmerrick]

Hi @SamProtas, thanks for your contribution!

In order for us to evaluate and accept your PR, we ask that you sign a contribution license agreement. It's all electronic and will take just minutes.

[cmerrick]

You did it @SamProtas!

Thank you for signing the Singer Contribution License Agreement.