refactor(cl):allow empty lib command

[luoliwoshang]

part of #434

with this mode, the lib command is not nessary, current need support this mode.

[codecov]

Codecov Report

Attention: Patch coverage is 66.66667% with 3 lines in your changes missing coverage. Please review.

Project coverage is 84.18%. Comparing base (0e3333d) to head (1596037).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
cl/internal/convert/package.go	66.66%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #491      +/-   ##
==========================================
- Coverage   84.35%   84.18%   -0.17%     
==========================================
  Files          27       27              
  Lines        2723     2713      -10     
==========================================
- Hits         2297     2284      -13     
- Misses        385      387       +2     
- Partials       41       42       +1     

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