fix(aws-lambda): update semconv package and readme

[JamieDanielson]

Which problem is this PR solving?

• updates Update usage of semantic conventions to new exported strings #2025
• updates Document instrumentation semantic conventions #1778
• finishes work from refactor(instr-aws-sdk): use exported strings for attributes #2142 😬

Short description of the changes

• Update @opentelemetry/semantic-conventions to ^1.22 for aws-lambda instrumentation
• Update README with new semantic convention package version and key

Note I inadvertently included some changes on #2142 when updating the aws-sdk instrumentation. This finishes that work by also updating the package and documenting in the README. I labeled as a fix as I'm not sure if there will be an issue with the current released version of aws-lambda instrumentation without the correct package (or if it will do the same as it seems to have done here, which I think is to pull from the next available package with these attributes)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.00%. Comparing base (dfb2dff) to head (dfc8514).
Report is 119 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2181      +/-   ##
==========================================
- Coverage   90.97%   90.00%   -0.98%     
==========================================
  Files         146      140       -6     
  Lines        7492     6903     -589     
  Branches     1502     1453      -49     
==========================================
- Hits         6816     6213     -603     
- Misses        676      690      +14     

see 48 files with indirect coverage changes