fix: supports write_precision for write Pandas DataFrame

[bednar]

Closes #245

Proposed Changes

The dataframe_serializer.py supports write_precision.

Checklist

• CHANGELOG.md updated
• Rebased/mergeable
• A test has been added if appropriate
• pytest tests completes successfully
• Commit messages are in semantic format
• Sign CLA (if not already signed)

[codecov-commenter]

Codecov Report

Merging #270 (51bd56c) into master (a2dbc0b) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #270      +/-   ##
==========================================
+ Coverage   92.56%   92.58%   +0.02%     
==========================================
  Files          27       27              
  Lines        2151     2158       +7     
==========================================
+ Hits         1991     1998       +7     
  Misses        160      160              

Impacted Files	Coverage Δ
...fluxdb_client/client/write/dataframe_serializer.py	98.78% <100.00%> (+0.11%)	⬆️
influxdb_client/client/write_api.py	99.06% <100.00%> (ø)

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