Python-blocks

Summary
We are excited to announce the release of version 0.1.8 of the blocks package, which includes tests.

Tests
Added new tests using pytest to cover the newly introduced classes and methods.

Using poetry:

poetry run pytest

Minor Update
New Features
`BlockUnion`: Introduced a new feature `BlockUnion` which outputs a pandas DataFrame. This functionality enhances the `sklearn` `FeatureUnion` processing capabilities by allowing users to combine multiple data blocks into a single DataFrame instead of using `hstack`.
Patch Update
Enhancements
`BaseTransformer`: Added a fit method to the `BaseTransformer` class. This patch improves the extensibility of `BaseTransformer`, enabling it to be more easily integrated with other components (e.i. `Pipeline`) that require a fitting process.

Fix BaseTransformer.