added Spring framework PDF (#4451)

* added Spring framework PDF

* Update free-programming-books.md

Fixed spelling

free-programming-books.md

@@ -1629,6 +1629,7 @@ Kerridge (PDF) (email address *requested*, not required)
 
 * [Building Applications with Spring 5 and Vue.js 2](https://www.packtpub.com/free-ebooks/building-applications-spring-5-and-vuejs-2) - James J. Ye (Packt account *required*)
 * [Software Architecture with Spring 5.0](https://www.packtpub.com/free-ebooks/software-architecture-spring-50) - René Enríquez, Alberto Salazar (Packt account *required*)
+* [Spring Framework Cookbook: Hot Recipes for Spring Framework](https://www.javacodegeeks.com/wp-content/uploads/2017/01/Spring-Framework-Cookbook.pdf) - JCGs (Java Code Geeks) (PDF)
 * [Spring Framework Notes for Professionals](https://books.goalkicker.com/SpringFrameworkBook) - Compiled from StackOverflow documentation
 * [Spring Framework Reference Documentation](https://docs.spring.io/spring/docs/current/spring-framework-reference/) - Rod Johnson et al.