Release 0.7.0

Linfa's 0.7.0 release mainly consists of improvements to Serde support. It also removes Approximate DBSCAN from linfa-clustering due to subpar performance and outdated dependencies.

Improvements and fixes

• Add array_from_gz_csv and array_from_csv in linfa-datasets.
• Make Serde support in linfa-linear, linfa-logistic, and linfa-ftrl optional.
• Add Serde support to linfa-preprocessing and linfa-bayes.
• Bump argmin to 0.8.1.
• Make licenses follow SPDX 2.1 license expression standard.

Removals

Approximate DBSCAN is an alternative implementation of the DBSCAN algorithm that trades precision for speed. However, the implementation in linfa-clustering is actually slower than the regular DBSCAN implementation. It also depends on the partitions crate, which is incompatible with current versions of Rust. Thus, we have decided to remove Approximate DBSCAN from Linfa. The Approximate DBSCAN types and APIs are now aliases to regular DBSCAN.