release v0.6.4

What's Changed

• Add explicit NumPy 1.x and 2.x compatibility coverage by Ilya Matiach (@imatiach-msft) in #190
• Normalize single-column prediction arrays by Ilya Matiach (@imatiach-msft) in #193
• release ml-wrappers 0.6.4 by Ilya Matiach (@imatiach-msft) in #192

Full Changelog: v0.6.3...v0.6.4