Fix missing cpu trainer

[ashleve]

What does this PR do?

Adds missing cpu.yaml trainer.

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• Did you make sure your PR does only one thing, instead of bundling different changes together?
• Did you list all the breaking changes introduced by this pull request?
• Did you test your PR locally with pytest command?
• Did you run pre-commit hooks with pre-commit run -a command?

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[codecov-commenter]

Codecov Report

Merging #402 (f6d7be2) into main (9dbef77) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #402   +/-   ##
=======================================
  Coverage   82.90%   82.90%           
=======================================
  Files          11       11           
  Lines         351      351           
=======================================
  Hits          291      291           
  Misses         60       60           

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