0.6.0: Kotlin 2.0, Kotlin/Native, Kotlin/Wasm

• Upgrade to Kotlin 2.0. Minimum user version is still 1.7 (#106 by @jillesvangurp)
• Adds Kotlin/Native (#103 by @jillesvangurp)
• Adds Kotlin/Wasm (#103 by @jillesvangurp)
• Add ValidationResult<T>.isValid (#113 by @jillesvangurp)