fix: write a dictionary-style object without tags

[bednar]

Closes #234

Proposed Changes

Added a default empty dict for tags in dictionary-style object.

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]

Codecov Report

Merging #235 (da97bca) into master (5f3ce1f) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #235   +/-   ##
=======================================
  Coverage   91.76%   91.76%           
=======================================
  Files          25       25           
  Lines        2003     2004    +1     
=======================================
+ Hits         1838     1839    +1     
  Misses        165      165           

Impacted Files	Coverage Δ
influxdb_client/client/write_api.py	99.05% <100.00%> (+<0.01%)	⬆️

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