Replace search.maven.org with central.sonatype.com (Kotlin#2243)

It will eventually be replaced: https://central.sonatype.org/faq/what-happened-to-search-maven-org/

Author: DRSchlaubi

README.md

@@ -5,7 +5,7 @@
 [![GitHub license](https://img.shields.io/badge/license-Apache%20License%202.0-blue.svg?style=flat)](http://www.apache.org/licenses/LICENSE-2.0)
 [![TeamCity build](https://img.shields.io/teamcity/http/teamcity.jetbrains.com/s/KotlinTools_KotlinxSerialization_Ko.svg)](https://teamcity.jetbrains.com/viewType.html?buildTypeId=KotlinTools_KotlinxSerialization_Ko&guest=1)
 [![Kotlin](https://img.shields.io/badge/kotlin-1.8.10-blue.svg?logo=kotlin)](http://kotlinlang.org)
-[![Maven Central](https://img.shields.io/maven-central/v/org.jetbrains.kotlinx/kotlinx-serialization-core/1.5.0)](https://search.maven.org/artifact/org.jetbrains.kotlinx/kotlinx-serialization-core/1.5.0/pom)
+[![Maven Central](https://img.shields.io/maven-central/v/org.jetbrains.kotlinx/kotlinx-serialization-core/1.5.0)](https://central.sonatype.com/artifact/org.jetbrains.kotlinx/kotlinx-serialization-core/1.5.0)
 [![KDoc link](https://img.shields.io/badge/API_reference-KDoc-blue)](https://kotlinlang.org/api/kotlinx.serialization/)
 [![Slack channel](https://img.shields.io/badge/chat-slack-blue.svg?logo=slack)](https://kotlinlang.slack.com/messages/serialization/)