semantic-conventions: update to v1.4.0 spec

[jtescher]

No description provided.

[codecov]

Codecov Report

Merging #570 (83ad388) into main (d70a537) will increase coverage by 0.0%.
The diff coverage is n/a.

@@          Coverage Diff          @@
##            main    #570   +/-   ##
=====================================
  Coverage   54.4%   54.4%           
=====================================
  Files         99      99           
  Lines       8642    8642           
=====================================
+ Hits        4708    4709    +1     
+ Misses      3934    3933    -1     

Impacted Files	Coverage Δ
opentelemetry/src/context.rs	92.9% <0.0%> (+0.7%)	⬆️

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