Bump kotlin.version from 1.6.10 to 1.6.20 (#823)

Bumps `kotlin.version` from 1.6.10 to 1.6.20.

Updates `kotlin-bom` from 1.6.10 to 1.6.20
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](https://github.com/JetBrains/kotlin/commits)

Updates `kotlin-maven-plugin` from 1.6.10 to 1.6.20

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

pom.xml

@@ -55,7 +55,7 @@
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <java.version>1.8</java.version>
-        <kotlin.version>1.6.10</kotlin.version>
+        <kotlin.version>1.6.20</kotlin.version>
         <github.global.server>github</github.global.server>
     </properties>