Add apk support

[LinuxSuRen]

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[codecov]

Codecov Report

Merging #257 (c499647) into master (ea4cba7) will decrease coverage by 0.02%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #257      +/-   ##
==========================================
- Coverage   26.19%   26.16%   -0.03%     
==========================================
  Files          28       28              
  Lines        1886     1888       +2     
==========================================
  Hits          494      494              
- Misses       1367     1369       +2     
  Partials       25       25              

Flag	Coverage Δ
unittests	26.16% <0.00%> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pkg/os/generic_installer.go	14.47% <0.00%> (-0.40%)	⬇️

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