[HttpClient] update network.protocol.version values as per specification

[vishweshbankwar]

Fixes #
Design discussion issue #

Changes

Assign values as per spec https://github.com/open-telemetry/semantic-conventions/blob/main/docs/http/http-spans.md#common-attributes

Merge requirement checklist

• CONTRIBUTING guidelines followed (nullable enabled, static analysis, etc.)
• Unit tests added/updated
• Appropriate CHANGELOG.md files updated for non-trivial changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

Merging #5006 (48f2776) into main (4ccee25) will decrease coverage by 0.19%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##             main    #5006      +/-   ##
==========================================
- Coverage   83.52%   83.33%   -0.19%     
==========================================
  Files         296      296              
  Lines       12467    12475       +8     
==========================================
- Hits        10413    10396      -17     
- Misses       2054     2079      +25     

Flag	Coverage Δ
unittests	83.33% <66.66%> (-0.19%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
...tp/Implementation/HttpHandlerDiagnosticListener.cs	73.50% <100.00%> (ø)
...ementation/HttpHandlerMetricsDiagnosticListener.cs	90.14% <100.00%> (ø)
...plementation/HttpWebRequestActivitySource.netfx.cs	82.71% <100.00%> (ø)
...strumentation.Http/Implementation/HttpTagHelper.cs	85.18% <50.00%> (-14.82%)	⬇️

... and 7 files with indirect coverage changes

[github-actions]

This PR was marked stale due to lack of activity and will be closed in 7 days. Commenting or Pushing will instruct the bot to automatically remove the label. This bot runs once per day.