Update readme (#3343)

Author: qwwdfsad

README.md

@@ -4,11 +4,11 @@
 [![JetBrains official project](https://jb.gg/badges/official.svg)](https://confluence.jetbrains.com/display/ALL/JetBrains+on+GitHub)
 [![GitHub license](https://img.shields.io/badge/license-Apache%20License%202.0-blue.svg?style=flat)](https://www.apache.org/licenses/LICENSE-2.0)
 [![Download](https://img.shields.io/maven-central/v/org.jetbrains.kotlinx/kotlinx-coroutines-core/1.6.3)](https://search.maven.org/artifact/org.jetbrains.kotlinx/kotlinx-coroutines-core/1.6.3/pom)
-[![Kotlin](https://img.shields.io/badge/kotlin-1.6.0-blue.svg?logo=kotlin)](http://kotlinlang.org)
+[![Kotlin](https://img.shields.io/badge/kotlin-1.6.21-blue.svg?logo=kotlin)](http://kotlinlang.org)
 [![Slack channel](https://img.shields.io/badge/chat-slack-green.svg?logo=slack)](https://kotlinlang.slack.com/messages/coroutines/)
 
 Library support for Kotlin coroutines with [multiplatform](#multiplatform) support.
-This is a companion version for the Kotlin `1.6.0` release.
+This is a companion version for the Kotlin `1.6.21` release.
 
 ```kotlin
 suspend fun main() = coroutineScope {
@@ -188,14 +188,6 @@ Kotlin/Native version of `kotlinx.coroutines` is published as
 [`kotlinx-coroutines-core-$platform`](https://mvnrepository.com/search?q=kotlinx-coroutines-core-) where `$platform` is 
 the target Kotlin/Native platform. [List of currently supported targets](https://github.com/Kotlin/kotlinx.coroutines/blob/master/gradle/compile-native-multiplatform.gradle#L16).
 
-
-Only single-threaded code (JS-style) on Kotlin/Native is supported in stable versions.
-Additionally, a special `-native-mt` version is released on a regular basis, for the state of multi-threaded coroutines support
-please follow the [corresponding issue](https://github.com/Kotlin/kotlinx.coroutines/issues/462) for the additional details.
-
-Since Kotlin/Native does not generally provide binary compatibility between versions, 
-you should use the same version of the Kotlin/Native compiler as was used to build `kotlinx.coroutines`. 
-
 ## Building and Contributing
 
 See [Contributing Guidelines](CONTRIBUTING.md).