Update dependency org.jetbrains.kotlin.android to v2.1.21 (#276)

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

Author: renovate[bot]

gradle/libs.versions.toml

@@ -3,7 +3,7 @@ sdk-target = "36"
 sdk-compile = "36"
 sdk-min = "21"
 agp = "8.10.0"
-kotlin = "2.1.20"
+kotlin = "2.1.21"
 versions = "0.52.0"
 dokka = "2.0.0"
 core-ktx = "1.16.0"