Narwhals v1.18.3

Changes

• release: Bump version to 1.18.2 (#1582)

✨ Enhancements

• feat/fix: Improve error message when trying to do unsupported group-by aggregation, and raise instead of giving inconsistent results (#1584)

🛠️ Other improvements

• refactor: PandasLikeExpr repr and init (#1585)

Thank you to all our contributors for making this release possible!
@MarcoGorelli, @anopsy and @camriddell