v4.1.5

This PR introduces a fix where unused files in the lookups directory, such as CSV or MLMODEL files that
are no longer referenced by a Lookup YML, could be included in the build of an app.
It also now ensures that CSV referenced by a lookup are syntactically valid CSV.

It also fixes a bug that caused contentctl test mode:changes to fail when an mlmodel file had been updated in the lookups directory.

What's Changed

• Fix mlmodel changes bug by @pyth0n1c in #199
• Parse and validate CSV files by @pyth0n1c in #200

Full Changelog: v4.1.4...v4.1.5