chore: add configuration for Dependabot

[bednar]

Proposed Changes

Added configuration for Dependabot.

Checklist

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

[codecov-commenter]

Codecov Report

Merging #465 (ac4d600) into master (161e202) will not change coverage.
The diff coverage is 87.50%.

@@           Coverage Diff           @@
##           master     #465   +/-   ##
=======================================
  Coverage   89.45%   89.45%           
=======================================
  Files          38       38           
  Lines        3292     3292           
=======================================
  Hits         2945     2945           
  Misses        347      347           

Impacted Files	Coverage Δ
influxdb_client/configuration.py	87.64% <0.00%> (ø)
influxdb_client/__init__.py	100.00% <100.00%> (ø)
influxdb_client/_async/api_client.py	51.25% <100.00%> (ø)
influxdb_client/_sync/api_client.py	73.11% <100.00%> (ø)
influxdb_client/version.py	100.00% <100.00%> (ø)

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[powersj]

Always happy to have dependabot. What prompted the change of CLIENT_VERISON to VERSION?

[bednar]

Always happy to have dependabot. What prompted the change of CLIENT_VERISON to VERSION?

Without this change the dependabot wasn't able to parse dependencies from setup.py.

https://github.com/dependabot/dependabot-core/blob/main/python/helpers/lib/parser.py