fix: Schema.addField does not correctly add value of type Date

[dblythy]

New Pull Request Checklist

• I am not disclosing a vulnerability.
• I am creating this PR in reference to an issue.

Issue Description

Schema.addField with type of date does not correctly convert date to iso object.

Related issue: #1545

Approach

Fixes addField for date type

TODOs before merging

• Add tests
• Add changes to documentation (guides, repository pages, in-code descriptions)

[parse-github-assistant]

I will reformat the title to use the proper commit message syntax.

[parse-github-assistant]

Thanks for opening this pull request!

• 🎉 We are excited about your hands-on contribution!

[dblythy]

This is the failing test that demonstrates the issue:

it('can add date field with default value', () => {
    const schema = new ParseSchema('NewSchemaTest');
    const date = new Date();
    schema.addDate('testField', { defaultValue: date });
    schema.addField('testField2', 'Date', { defaultValue: date });
    expect(schema._fields.testField.defaultValue).toEqual({ __type: 'Date', iso: date });
    expect(schema._fields.testField2.defaultValue).toEqual({ __type: 'Date', iso: date }); // Before this PR, this is just `date.toISOString()`
  });

[codecov]

Codecov Report

Base: 99.94% // Head: 99.94% // Increases project coverage by +0.00% 🎉

Coverage data is based on head (25aab0b) compared to base (473949d).
Patch coverage: 100.00% of modified lines in pull request are covered.

❗ Current head 25aab0b differs from pull request most recent head 9d7fd55. Consider uploading reports for the commit 9d7fd55 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##            alpha    parse-community/parse-server#1544   +/-   ##
=======================================
  Coverage   99.94%   99.94%           
=======================================
  Files          61       61           
  Lines        5954     5955    +1     
  Branches     1359     1360    +1     
=======================================
+ Hits         5951     5952    +1     
  Misses          3        3           

Impacted Files	Coverage Δ
src/ParseSchema.js	100.00% <100.00%> (ø)

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[mtrezza]

Looks good, ready for merge?

[dblythy]

Yep!

[parseplatformorg]

🎉 This change has been released in version 3.5.0-alpha.3

[parseplatformorg]

🎉 This change has been released in version 3.5.0-beta.1

[parseplatformorg]

🎉 This change has been released in version 3.5.0