[Instrumentation.AWSLambda] Replace .NET 6 target with .NET 8 and add .NET Standard 2.0

[joegoldman2]

Changes

Replace .NET 6 target, which will be very soon out of support, with .NET 8 and add support for .NET Standard 2.0.

Merge requirement checklist

• CONTRIBUTING guidelines followed (license requirements, 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

All modified and coverable lines are covered by tests ✅

Project coverage is 84.78%. Comparing base (71655ce) to head (c9983c2).
Report is 481 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #2140       +/-   ##
===========================================
+ Coverage   73.91%   84.78%   +10.86%     
===========================================
  Files         267       20      -247     
  Lines        9615      368     -9247     
===========================================
- Hits         7107      312     -6795     
+ Misses       2508       56     -2452     

Flag	Coverage Δ
unittests-Instrumentation.AWS	84.78% <ø> (?)

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

see 274 files with indirect coverage changes

[Oberon00]

I would prefer waiting at least for the "Block function create" date (Feb 28, 2025) https://docs.aws.amazon.com/lambda/latest/dg/lambda-runtimes.html

[joegoldman2]

I would prefer waiting at least for the "Block function create" date (Feb 28, 2025) https://docs.aws.amazon.com/lambda/latest/dg/lambda-runtimes.html

The addition of .NET Standard 2.0 target should be fine for people who are targeting .NET 6 and less.

[Oberon00]

That looks fine to me. Do we even need .NET 8 separately if we have netstandard2.0 as target?

[CodeBlanch]

LGTM