fix: get version from X-Influxdb-Version header

[bednar]

Closes #296

Proposed Changes

Fixed getting version from X-Influxdb-Version header.

Checklist

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

[codecov-commenter]

Codecov Report

Merging #297 (7e577dc) into master (3a4bcb0) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #297      +/-   ##
==========================================
+ Coverage   89.24%   89.26%   +0.01%     
==========================================
  Files          73       73              
  Lines        6332     6332              
==========================================
+ Hits         5651     5652       +1     
+ Misses        681      680       -1     

Impacted Files	Coverage Δ
Client/InfluxDBClient.cs	96.46% <ø> (ø)
Client.Core/Internal/AbstractRestClient.cs	96.77% <100.00%> (ø)
Client/Internal/RetryAttempt.cs	100.00% <0.00%> (+0.97%)	⬆️

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