ci: Run test suite against ParseStream

[dplewis]

New Pull Request Checklist

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

Issue Description

The test suite runs against cURL, this PR adds stream context tests to the CI. We should support both http clients.

// set curl http client (default if none set)
ParseClient::setHttpClient(new ParseCurlHttpClient());

// set stream http client
// ** requires 'allow_url_fopen' to be enabled in php.ini **
ParseClient::setHttpClient(new ParseStreamHttpClient());

TODOs before merging

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

[parse-github-assistant]

Thanks for opening this pull request!

• ❌ Please link an issue that describes the reason for this pull request, otherwise your pull request will be closed. Make sure to write it as Closes: #123 in the PR description, so I can recognize it.

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.12 🎉

Comparison is base (d46107e) 98.48% compared to head (5062f70) 98.60%.

❗ Current head 5062f70 differs from pull request most recent head 9853c44. Consider uploading reports for the commit 9853c44 to get more accurate results

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #509      +/-   ##
============================================
+ Coverage     98.48%   98.60%   +0.12%     
- Complexity     1060     1062       +2     
============================================
  Files            38       38              
  Lines          3225     3229       +4     
============================================
+ Hits           3176     3184       +8     
+ Misses           49       45       -4     

Impacted Files	Coverage Δ
src/Parse/HttpClients/ParseStream.php	100.00% <100.00%> (+22.22%)	⬆️
src/Parse/ParseClient.php	95.23% <100.00%> (-0.44%)	⬇️

... and 1 file with indirect coverage changes

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[mtrezza]

Looks good!

[parseplatformorg]

🎉 This change has been released in version 2.2.0