Fix Apache license headers

mvnw

mvnw.cmd

pom.xml

readme.md

...ringframework/samples/petclinic/PetClinicApplication.java

...g/springframework/samples/petclinic/model/BaseEntity.java

.../springframework/samples/petclinic/model/NamedEntity.java

...a/org/springframework/samples/petclinic/model/Person.java

...springframework/samples/petclinic/model/package-info.java

...va/org/springframework/samples/petclinic/owner/Owner.java

...ingframework/samples/petclinic/owner/OwnerController.java

...ingframework/samples/petclinic/owner/OwnerRepository.java

...java/org/springframework/samples/petclinic/owner/Pet.java

...pringframework/samples/petclinic/owner/PetController.java

...pringframework/samples/petclinic/owner/PetRepository.java

.../org/springframework/samples/petclinic/owner/PetType.java

...ngframework/samples/petclinic/owner/PetTypeFormatter.java

...springframework/samples/petclinic/owner/PetValidator.java

...ingframework/samples/petclinic/owner/VisitController.java

...ramework/samples/petclinic/system/CacheConfiguration.java