Log Message:
databases/diesel-cli: update to 2.2.8

Fixed

 - Allow #[diesel(check_for_backend(_))] to check fields with #[diesel(embed)] \ 
annotations
 - Improve custom compile error message around CompatibleType
 - Fix a bug that restricted the number of allowed columns in COPY FROM \ 
statements to 12
 - Expose some SqliteValue helper functions
 - Use consistent whitespace in ASC/DESC, DISTINCT ON, and DELETE FROM clauses