@sitevision/api - Use copyfiles instead of cp

[kling90]

When running yarn build in packages/api I get the following error in Windows (PowerShell):

$ rimraf dist/ && babel src --out-dir dist --copy-files && cp package.json README.md dist/
Successfully compiled 37 files with Babel (1293ms).
'cp' is not recognized as an internal or external command,
operable program or batch file.
error Command failed with exit code 1.

Changed to copyfiles wich is not tied to a specific OS command for copying files.

[albinohrn]

Thanks! / :)