Liesel v0.3.1

What's Changed

• Update linear regression tutorial and readme by @jobrachem in #226
• Add some informative error messages (closes #222, #219) by @jobrachem in #224
• Transform Variables Without Distributions (closes #216) by @jobrachem in #223
• Fixes issue with custom log prob in liesel models by @wiep in #228

Full Changelog: v0.3.0...v0.3.1