Remove JCenter from everywhere

Author: ileasile

docs/README-STUB.md

@@ -108,7 +108,6 @@ and try again.
 ### Default repositories
 
 The following maven repositories are included by default:
- - [Bintray JCenter](https://jcenter.bintray.com)
  - [Maven Central](https://repo.maven.apache.org/maven2)
  - [JitPack](https://jitpack.io/)
 

docs/README.md

@@ -109,7 +109,6 @@ and try again.
 ### Default repositories
 
 The following maven repositories are included by default:
- - [Bintray JCenter](https://jcenter.bintray.com)
  - [Maven Central](https://repo.maven.apache.org/maven2)
  - [JitPack](https://jitpack.io/)
 

jupyter-lib/shared-compiler/src/main/kotlin/org/jetbrains/kotlinx/jupyter/config/defaultImports.kt

@@ -3,7 +3,6 @@ package org.jetbrains.kotlinx.jupyter.config
 import kotlin.script.experimental.dependencies.RepositoryCoordinates
 
 val defaultRepositories = arrayOf(
-    "https://jcenter.bintray.com/",
     "https://repo.maven.apache.org/maven2/",
     "https://jitpack.io/",
 ).map(::RepositoryCoordinates)