Update CHANGELOG for 1.6.0 release of AspNetCore and Http instrumentation libraries

[utpilla]

Changes

• Update CHANGELOG for 1.6.0 release of AspNetCore and Http instrumentation libraries
• Update public API files

• Appropriate CHANGELOG.md files updated for non-trivial changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

Merging #5171 (d5a755e) into main (a736574) will increase coverage by 0.02%.
Report is 3 commits behind head on main.
The diff coverage is 100.00%.

❗ Current head d5a755e differs from pull request most recent head 91a4cc7. Consider uploading reports for the commit 91a4cc7 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5171      +/-   ##
==========================================
+ Coverage   83.46%   83.48%   +0.02%     
==========================================
  Files         297      297              
  Lines       12368    12366       -2     
==========================================
+ Hits        10323    10324       +1     
+ Misses       2045     2042       -3     

Flag	Coverage Δ
unittests	83.48% <100.00%> (+0.02%)	⬆️

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

Files	Coverage Δ
...ementation/HttpHandlerMetricsDiagnosticListener.cs	88.23% <100.00%> (-0.23%)	⬇️
...plementation/HttpWebRequestActivitySource.netfx.cs	80.77% <100.00%> (-0.04%)	⬇️

... and 7 files with indirect coverage changes