fix(deps): update kotlin monorepo to v1.9.21 (#123)

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

Author: renovate[bot]

gradle/libs.versions.toml

@@ -17,7 +17,7 @@ coil = "2.5.0"
 google-android-material = "1.10.0"
 
 jetbrains-dokka = "1.9.10"
-jetbrains-kotlin = "1.9.20"
+jetbrains-kotlin = "1.9.21"
 jetbrains-kotlinx-coroutines = "1.7.3"
 jetbrains-kotlinx-datetime = "0.4.1"
 jetbrains-kotlinx-serialization = "1.6.1"