sw_concepts: replace broken link to "Head First Design Patterns"

topics/sw_concepts/sw_concept_slides.md

@@ -556,7 +556,7 @@ Links
 
 [Java Design Patterns]: https://github.com/iluwatar/java-design-patterns
 [Refactoring Guru]: https://refactoring.guru/
-[Head First Design Patterns]: https://archive.org/details/head-first-design
+[Head First Design Patterns]: https://github.com/ajitpal/BookBank/blob/master/%5BO%60Reilly.%20Head%20First%5D%20-%20Head%20First%20Design%20Patterns%20-%20%5BFreeman%5D.pdf
 [Clean Code]: https://books.google.ch/books/about/Clean_Code.html?id=_i6bDeoCQzsC&redir_esc=y
 [Dependency Inversion Principle]: https://web.archive.org/web/20110714224327/http://www.objectmentor.com/resources/articles/dip.pdf
 [Open-Closed Priniple]: https://web.archive.org/web/20060822033314/http://www.objectmentor.com/resources/articles/ocp.pdf