fix(tests): compatibility with Pandas 1.5

[bednar]

Related to https://app.circleci.com/pipelines/github/influxdata/influxdb-client-python/2046/workflows/8fdf747c-83b7-4fed-a1e7-647c216f211f

Proposed Changes

Use correct start bound for PeriodIndex to be compatible with Pandas 1.5.

• https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#offset-aliases

Checklist

• Rebased/mergeable
• pytest tests completes successfully
• Commit messages are conventional
• Sign CLA (if not already signed)

[codecov-commenter]

Codecov Report

Base: 90.39% // Head: 90.59% // Increases project coverage by +0.19% 🎉

Coverage data is based on head (33c4cdc) compared to base (da73522).
Patch has no changes to coverable lines.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #503      +/-   ##
==========================================
+ Coverage   90.39%   90.59%   +0.19%     
==========================================
  Files          39       39              
  Lines        3353     3380      +27     
==========================================
+ Hits         3031     3062      +31     
+ Misses        322      318       -4     

Impacted Files	Coverage Δ
influxdb_client/client/flux_csv_parser.py	98.38% <0.00%> (+0.02%)	⬆️
influxdb_client/client/write/point.py	96.77% <0.00%> (+0.06%)	⬆️
influxdb_client/_sync/api_client.py	73.11% <0.00%> (+0.29%)	⬆️
influxdb_client/client/write_api.py	99.03% <0.00%> (+0.50%)	⬆️
influxdb_client/_async/api_client.py	64.15% <0.00%> (+0.52%)	⬆️
influxdb_client/client/_base.py	97.35% <0.00%> (+0.62%)	⬆️
influxdb_client/configuration.py	87.64% <0.00%> (+0.89%)	⬆️
influxdb_client/client/util/helpers.py	100.00% <0.00%> (+3.57%)	⬆️

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[powersj]

LGTM