Add PatientAge in DicomSeriesMetadataName

[chhsiao1981]

1. add PatientAge in DicomSeriesMetadataName.
2. force value to be str for regex in match.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 67.68%. Comparing base (469070d) to head (132bed4).
⚠️ Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
src/serie/match.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master       #2      +/-   ##
==========================================
+ Coverage   67.55%   67.68%   +0.12%     
==========================================
  Files          10       10              
  Lines         262      263       +1     
==========================================
+ Hits          177      178       +1     
  Misses         85       85              

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