Fix the maven plugin build on Java 11

[mmvpm]

Description

After upgrading Java, Kotlin and Gradle versions build and publishing of the utbot maven plugin are fails, so we need to fix it

To Reproduce

Try to publish the utbot-maven module: https://github.com/UnitTestBot/UTBotJava/blob/main/utbot-maven/docs/utbot-maven.md#how-to-test

Expected behavior

The plugin was published to the local repository