Update Kotlin and kotlinx dependencies

Author: jakobkmar

buildSrc/build.gradle.kts

@@ -7,5 +7,5 @@ repositories {
 }
 
 dependencies {
-    implementation(kotlin("gradle-plugin", "1.4.32"))
+    implementation(kotlin("gradle-plugin", "1.5.20"))
 }

simplekotlinmail-core/build.gradle.kts

@@ -5,7 +5,7 @@ plugins {
     `java-version-script`
     `maven-publish-script`
 
-    kotlin("plugin.serialization") version "1.4.32"
+    kotlin("plugin.serialization") version "1.5.20"
 }
 
 /**
@@ -18,8 +18,8 @@ dependencies {
     api("org.simplejavamail:smime-module:${Versions.simpleJavaMail}")
 
     // COROUTINES
-    api("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.4.3")
+    api("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.5.1")
 
     // SERIALIZATION
-    implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.1.0")
+    implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.2.2")
 }