docs: ✏️ Updates changelog to 0.3.1

Author: asm0dey

CHANGELOG.md

@@ -1,5 +1,16 @@
 # Changelog
 
+## 0.3.1 (05/08/2020)
+- [chore: 🤖 Version bump to 0.3.1](https://github.com/JetBrains/kotlin-spark-api/commit/88d4e31cd6d76fe1fc0b9c10a078658aa6178e36) - @asm0dey
+- [test: 💍 Adds integration and more unit tests](https://github.com/JetBrains/kotlin-spark-api/commit/bca98f77b743c9456882f49702f9cea55d153320) - @asm0dey
+- [fix: 🐛 Fixes incorrect order of fields in data class](https://github.com/JetBrains/kotlin-spark-api/commit/56bc82f9ff0de6948386e8c4a330ba715285ad55) - @asm0dey
+- [fix: 🐛 Fixes incorrect handling of primitive types](https://github.com/JetBrains/kotlin-spark-api/commit/868e47919d41309e1ebebc327acdd53e3df094ea) - @asm0dey
+- [Bump klaxon from 5.2 to 5.3](https://github.com/JetBrains/kotlin-spark-api/commit/edfd06d4895ded7772a42d7e13e2eb2aed8031bf) - @dependabot[bot]
+- [Updated README.md (#32)](https://github.com/JetBrains/kotlin-spark-api/commit/c2cc6fe7e7a4d5e0d501ab0a75e371c6cc041d77) - @MKhalusova
+- [Bump kotest.version from 4.1.1 to 4.1.3](https://github.com/JetBrains/kotlin-spark-api/commit/a1ca5fe8c11c7aeeb70a8335c2252549e1cc7f81) - @dependabot[bot]
+
+---
+
 ## 0.3.0 (08/07/2020)
 - [Version bump to 0.3.0](https://github.com/JetBrains/kotlin-spark-api/commit/0d5bcf57575d8906a219b4143a67df8939c46b0c) - @asm0dey
 - [Inproves README — adds information on collection of data from Dataset](https://github.com/JetBrains/kotlin-spark-api/commit/d81b98622ac816c9224f980d92407249333cf6d0) - @asm0dey