Bump kotlin.version from 2.0.0 to 2.0.21 (#407)

Bumps `kotlin.version` from 2.0.0 to 2.0.21.

Updates `org.jetbrains.kotlin:kotlin-maven-plugin` from 2.0.0 to 2.0.21

Updates `org.jetbrains.kotlin:kotlin-stdlib-jdk8` from 2.0.0 to 2.0.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v2.0.0...v2.0.21)

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlin:kotlin-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.jetbrains.kotlin:kotlin-stdlib-jdk8
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

hamming-error-correction/pom.xml

@@ -295,7 +295,7 @@
     </build>
 
     <properties>
-        <kotlin.version>2.0.0</kotlin.version>
+        <kotlin.version>2.0.21</kotlin.version>
         <junit.version>5.10.3</junit.version>
         <jmh.version>1.37</jmh.version>
         <jmh.generator>default</jmh.generator>

kotlin-collections/pom.xml

@@ -8,7 +8,7 @@
     <version>1.0</version>
 
     <properties>
-        <kotlin.version>2.0.0</kotlin.version>
+        <kotlin.version>2.0.21</kotlin.version>
         <junit.version>5.10.3</junit.version>
         <mockito.version>2.8.0</mockito.version>
     </properties>

kotlin-null-nonsafety/pom.xml

@@ -8,7 +8,7 @@
     <version>1.0</version>
 
     <properties>
-        <kotlin.version>2.0.0</kotlin.version>
+        <kotlin.version>2.0.21</kotlin.version>
     </properties>
 
     <dependencies>

kotlin-type-inference/pom.xml

@@ -8,7 +8,7 @@
     <version>1.0</version>
 
     <properties>
-        <kotlin.version>2.0.0</kotlin.version>
+        <kotlin.version>2.0.21</kotlin.version>
         <junit.version>5.10.3</junit.version>
         <mockito.version>2.8.0</mockito.version>
     </properties>