fix(deps): update kotlin-ksp-compose to v2.1.21 (#558)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

gradle/libs.versions.toml

@@ -3,7 +3,7 @@ androidGradlePlugin = "8.7.2"
 # For updating Kotlin and Compose Compiler version, see:
 # https://github.com/JetBrains/compose-multiplatform/blob/master/VERSIONING.md#kotlin-compatibility
 # https://developer.android.com/jetpack/androidx/releases/compose-kotlin?#pre-release_kotlin_compatibility
-kotlin = "2.1.20"
+kotlin = "2.1.21"
 
 androidDesugarJdkLibs = "2.1.3"
 apollographql = "3.8.5"