Add licensing details for the book's code
Add licensing details for the book's code

learning-spring-boot/learning-spring-boot-code,learning-spring-boot/learning-spring-boot-code-1.2,learning-spring-boot/learning-spring-boot-code,learning-spring-boot/learning-spring-boot-code-1.2,learning-spring-boot/learning-spring-boot-code-1.2,learning-spring-boot/learning-spring-boot-code,trifonnt/_book-learning-spring-boot-code,trifonnt/_book-learning-spring-boot-code