sf-hamilton-1.19.0 Release

What's Changed

• Clarifies the subdag example by @elijahbenizzy in #82
• Rewrites README.md opener by @elijahbenizzy in #89
• Adds shortened main.md for docs by @skrawcz in #88
• Adds ability to use variables with the driver.execute function #86 by @skrawcz in #87
• Pyspark udf support by @skrawcz in #83
• Supports delayed evaluation of annotations by @elijahbenizzy in #92
• Feature engineering in multiple contexts examples by @skrawcz in #94
• Utilizes proper python types rather than numpy types by @elijahbenizzy in #100
• Bump version by @skrawcz in #102

Full Changelog: sf-hamilton-1.18.0...sf-hamilton-1.19.0