feat: Add context in ParseObject

[mbfakourii]

Pull Request

• Report security issues confidentially.
• Any contribution is under this license.
• Link this pull request to an issue.

Issue

Added context in the save and create and update functions of the ParseObject class.

Closes: #672

Approach

How to use:

ParseObject object = ParseObject(className);
.
.
.
object.save(context: {
    "key","value"
});

Tasks

• Add tests
• Add changes to documentation (guides, repository pages, code comments)

[parse-github-assistant]

Thanks for opening this pull request!

[codecov]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (088bfbc) 39.60% compared to head (33b761f) 39.64%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #970      +/-   ##
==========================================
+ Coverage   39.60%   39.64%   +0.04%     
==========================================
  Files          60       60              
  Lines        3333     3337       +4     
==========================================
+ Hits         1320     1323       +3     
- Misses       2013     2014       +1     

Files	Coverage Δ
packages/dart/lib/src/objects/parse_file_base.dart	68.75% <ø> (ø)
...kages/dart/lib/src/objects/parse_installation.dart	28.92% <ø> (ø)
packages/dart/lib/src/objects/parse_user.dart	1.27% <ø> (ø)
packages/dart/lib/src/objects/parse_object.dart	94.90% <80.00%> (-0.67%)	⬇️

... and 1 file with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[mbfakourii]

The error related to Test Flutter beta has been resolved in this PR

[mtrezza]

Could you add a changelog entry?

[mbfakourii]

Could you add a changelog entry?

Done

[mtrezza]

Looks good! Waiting for #969 to be merged.