Add a changelog

Author: ilya-g

CHANGELOG.md

@@ -0,0 +1,20 @@
+# CHANGELOG
+
+## 0.1.1
+
+#### Fixes
+ 
+- Fix a crash when getting the current time on iOS 9 ([#52](https://github.com/Kotlin/kotlinx-datetime/issues/52))
+- Wrong answers in some cases when adding date-based units to instants on Darwin and Windows ([#51](https://github.com/Kotlin/kotlinx-datetime/issues/51)) 
+
+#### Features
+
+- Zone-agnostic time-based arithmetic on Instants, e.g. `Instant.plus(value, DateTimeUnit.TimeBased)`
+- Add `Instant.fromEpochSeconds(epochSeconds: Long, nanosecondAdjustment: Int)` construction function
+- Introduce `minus` operations complementary to existing `plus` arithmetic operations ([#42](https://github.com/Kotlin/kotlinx-datetime/issues/42))
+
+## 0.1.0
+
+#### Initial implementation 
+
+A minimal, but still valuable multiplatform implementation of date and time types.