docs: fix typo in README.md

[Erick2280]

This PR corrects a typo for the word "Semantic" in README.md.

[codecov]

Codecov Report

Merging #290 (9933182) into master (295bc92) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #290   +/-   ##
=======================================
  Coverage   95.67%   95.67%           
=======================================
  Files          26       26           
  Lines         670      670           
  Branches      112      112           
=======================================
  Hits          641      641           
  Misses         28       28           
  Partials        1        1           

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[wovalle]

Thanks!