fix: pin junit-platform-launcher to JUnit 6.0.3

In JUnit 6, Platform and Jupiter versions are aligned (both 6.0.3),
unlike JUnit 5 where Platform was 1.x and Jupiter was 5.x.
Explicitly pins junit-platform-launcher to avoid unintended version
resolution.

Co-authored-by: Jon Haddad <rustyrazorblade@users.noreply.github.com>

Author: github-actions[bot]

gradle/libs.versions.toml

@@ -93,7 +93,7 @@ jackson-datatype-jsr310 = { module = "com.fasterxml.jackson.datatype:jackson-dat
 
 # Testing
 junit-jupiter = { module = "org.junit.jupiter:junit-jupiter-engine", version.ref = "jupiter" }
-junit-platform-launcher = { module = "org.junit.platform:junit-platform-launcher" }
+junit-platform-launcher = { module = "org.junit.platform:junit-platform-launcher", version.ref = "jupiter" }
 assertj-core = { module = "org.assertj:assertj-core", version.ref = "assertj" }
 mockito-kotlin = { module = "org.mockito.kotlin:mockito-kotlin", version.ref = "mockito-kotlin" }
 testcontainers-core = { module = "org.testcontainers:testcontainers", version.ref = "testcontainers" }