Update kotlin monorepo to v2.0.20

[renovate]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
org.jetbrains.kotlin:kotlin-maven-plugin (source)	2.0.10 -> 2.0.20
org.jetbrains.kotlin:kotlin-compiler (source)	2.0.10 -> 2.0.20
org.jetbrains.kotlin:kotlin-stdlib-jdk8 (source)	2.0.10 -> 2.0.20

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Release Notes

JetBrains/kotlin (org.jetbrains.kotlin:kotlin-maven-plugin)

v2.0.20

Compare Source

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Configuration

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[coveralls]

coverage: 100.0%. remained the same
when pulling 9c0d748 on renovate/kotlin-monorepo
into e89fd77 on master.