Update ksp to v2.0.21-1.0.28

Author: renovate[bot]

gradle/libs.versions.toml

@@ -5,7 +5,7 @@ compileSdk = "34"
 agp = "8.6.1"
 kotlin = "2.0.20"
 java = "17"
-ksp = "2.0.20-1.0.25"
+ksp = "2.0.21-1.0.28"
 triplet-play = "3.11.0"
 protobuf-plugin = "0.9.4"