Fetch retry

[kp-cat]

Describe the purpose of your pull request

• Config fetch retry logic
• Accept only 200 status code response
• Empty string + null Config JSON validation
• Log CF Ray ID

Related issues (only if applicable)

• https://trello.com/c/bMad80Fm
• https://trello.com/c/uhARaUbh
• https://trello.com/c/iCm8OlJv
• https://trello.com/c/zM7cDRqq

Requirement checklist (only if applicable)

• I have covered the applied changes with automated tests.
• I have executed the full automated test set against my changes.
• I have validated my changes against all supported platform versions.
• I have read and accepted the contribution agreement.

[codecov]

Codecov Report

❌ Patch coverage is 99.20635% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 98.58%. Comparing base (afbd8bf) to head (1303c39).

Files with missing lines	Patch %	Lines
lib/configcat/version.rb	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #46      +/-   ##
==========================================
+ Coverage   98.54%   98.58%   +0.04%     
==========================================
  Files          40       40              
  Lines        3358     3466     +108     
==========================================
+ Hits         3309     3417     +108     
  Misses         49       49              

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[adams85]

Almost there, only a minor piece is missing: other SDKs also log the CF Ray ID for 1104 errors. (E.g., https://github.com/configcat/java-sdk/blob/0b6875f20161546635c2f2a1f08dc355834cc1c6/src/main/java/com/configcat/ConfigFetcher.java#L89)

Could you add this here too?

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud