Dependency(deps): Bump spotless-maven-plugin from 2.20.2 to 2.21.0#4

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dependabot/maven/com.diffplug.spotless-spotless-maven-plugin-2.21.0SimDing/JPlag:dependabot/maven/com.diffplug.spotless-spotless-maven-plugin-2.21.0Copy head branch name to clipboard