Update README.md for 0.3.4 release

Author: qurbonzoda

README.md

@@ -114,62 +114,44 @@ collection.mutate { some_actions_on(it) }
 
 > Note that the library is experimental and the API is subject to change.
 
-The library is published to [kotlinx](https://bintray.com/kotlin/kotlinx/kotlinx.collections.immutable) bintray repository and available in jcenter too.
+The library is published to Maven Central repository.
 
-The library depends on the Kotlin Standard Library of the version at least `1.4.0`.
+The library depends on the Kotlin Standard Library of the version at least `1.4.30`.
 
 ### Gradle
 
-Add the bintray repository:
+Add the Maven Central repository:
 
 ```groovy
 repositories {
-    jcenter()
+    mavenCentral()
 }
 ```
 
-In multiplatform projects add the following dependency to the common source set:
+Add the library to dependencies of the platform source set, e.g.:
 
 ```groovy
 kotlin {
     sourceSets {
         commonMain {
              dependencies {
-                 implementation("org.jetbrains.kotlinx:kotlinx-collections-immutable:0.3.3")
+                 implementation("org.jetbrains.kotlinx:kotlinx-collections-immutable:0.3.4")
              }
         }
     }
 }
 ```
 
-To use the library in a JVM-only project add the platform to the artifact name, e.g.:
-
-```groovy
-implementation("org.jetbrains.kotlinx:kotlinx-collections-immutable-jvm:0.3.3")
-```
-
 ### Maven
 
-Add the bintray repository to `<repositories>` section:
-
-```xml
-<repository>
-    <snapshots>
-        <enabled>false</enabled>
-    </snapshots>
-    <id>jcenter</id>
-    <name>jcenter</name>
-    <url>https://jcenter.bintray.com/</url>
-</repository>
-```
-
+The Maven Central repository is available for dependency lookup by default. 
 Add dependencies (you can also add other modules that you need):
 
 ```xml
 <dependency>
     <groupId>org.jetbrains.kotlinx</groupId>
     <artifactId>kotlinx-collections-immutable-jvm</artifactId>
-    <version>0.3.3</version>
+    <version>0.3.4</version>
 </dependency>
 ```