chore(deps): update dependency com.ncorti.ktfmt.gradle to v0.21.0

Author: renovate[bot]

gradle/libs.versions.toml

@@ -12,7 +12,7 @@ kotest = "5.9.1"
 kotlin = "1.9.25"
 kover = "0.8.3"
 ksp = "1.9.25-1.0.20"
-ktfmt = "0.18.0"
+ktfmt = "0.21.0"
 micronaut = "4.4.2"
 shadow = "8.1.1"
 spotless = "7.0.2"