Set timeout for GitHub GraphQL API

[kitsuyui]

There was no timeout setting, and even if an error occurred, only No data found was output.
This is the worst user interface and makes debugging difficult.
Resolve this.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 15 lines in your changes missing coverage. Please review.

Project coverage is 76.38%. Comparing base (f829665) to head (bbf5fe2).

Files with missing lines	Patch %	Lines
src/github/api.rs	0.00%	15 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #582      +/-   ##
==========================================
- Coverage   77.00%   76.38%   -0.62%     
==========================================
  Files          19       19              
  Lines        1857     1872      +15     
==========================================
  Hits         1430     1430              
- Misses        427      442      +15     

Flag	Coverage Δ
unittests	76.38% <0.00%> (-0.62%)	⬇️

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