fix: Time zone data not set in ParseInstallation

[mbfakourii]

New Pull Request Checklist

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

Issue Description

fix ParseInstallation timeZone missing

Closes: #96

Approach

Added a new way to get the time zone name

TODOs before merging

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

[parse-github-assistant]

Thanks for opening this pull request!

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

[codecov]

Codecov Report

Base: 13.63% // Head: 15.13% // Increases project coverage by +1.49% 🎉

Coverage data is based on head (d48de70) compared to base (cd6b544).
Patch coverage: 100.00% of modified lines in pull request are covered.

❗ Current head d48de70 differs from pull request most recent head d99c862. Consider uploading reports for the commit d99c862 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #811      +/-   ##
==========================================
+ Coverage   13.63%   15.13%   +1.49%     
==========================================
  Files          47       47              
  Lines        2846     2855       +9     
==========================================
+ Hits          388      432      +44     
+ Misses       2458     2423      -35     

Impacted Files	Coverage Δ
packages/dart/lib/parse_server_sdk.dart	28.57% <ø> (ø)
...kages/dart/lib/src/objects/parse_installation.dart	28.92% <100.00%> (+28.92%)	⬆️
packages/dart/lib/src/objects/parse_base.dart	46.78% <0.00%> (+1.83%)	⬆️
packages/dart/lib/src/data/parse_core_data.dart	71.73% <0.00%> (+4.34%)	⬆️
...ckages/dart/lib/src/storage/core_store_memory.dart	17.24% <0.00%> (+17.24%)	⬆️

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[mtrezza]

Could you add a test?

[mbfakourii]

Could you add a test?

test added

[mtrezza]

Looks good! If you would like to add the changelog entry, then we can publish a release.

[mbfakourii]

Looks good! If you would like to add the changelog entry, then we can publish a release.

added

[mtrezza]

Looks good!