fix: set CharsetReader and Entity when reading pom.xml

[cuixq]

#1321

If non UTF-8 encoding is declared in pom.xml, we need to set CharsetReader to avoid the error.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 90.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 68.49%. Comparing base (f492e39) to head (0d7258d).

Files with missing lines	Patch %	Lines
internal/resolution/manifest/maven.go	50.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1325      +/-   ##
==========================================
- Coverage   68.49%   68.49%   -0.01%     
==========================================
  Files         177      177              
  Lines       17155    17157       +2     
==========================================
+ Hits        11750    11751       +1     
- Misses       4766     4767       +1     
  Partials      639      639              

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