Fix NPE in CrudRepositoryExtensions

Author: OsaSoft

src/main/kotlin/org/springframework/data/repository/CrudRepositoryExtensions.kt

@@ -23,4 +23,4 @@ package org.springframework.data.repository
  * @author Sebastien Deleuze
  * @since 2.1.4
  */
-fun <T, ID> CrudRepository<T, ID>.findByIdOrNull(id: ID): T? = findById(id!!).orElse(null)
+fun <T, ID: Any> CrudRepository<T, ID>.findByIdOrNull(id: ID): T? = findById(id).orElse(null)