feat: Add dateUpdated field to Post model and update PostController

[baserrato]

This pull request introduces several changes to the Post class, PostController class, PostRepository interface, and PostTest class in the com.liatrio.dojo.devopsknowledgeshareapi package. The most significant changes include the addition of a dateUpdated field in the Post class, a new PUT request method in the PostController class, new search methods in the PostRepository interface, and new test cases in the PostTest class.

Changes to the Post class:

• src/main/java/com/liatrio/dojo/devopsknowledgeshareapi/Post.java: Added a new dateUpdated field with its respective setter and getter methods. This allows posts to track their last update time.

Changes to the PostController class:

• src/main/java/com/liatrio/dojo/devopsknowledgeshareapi/PostController.java: Added a new PUT request method putPost, which updates an existing post with the provided id. If the post does not exist, it throws an IllegalArgumentException.

Changes to the PostRepository interface:

• src/main/java/com/liatrio/dojo/devopsknowledgeshareapi/PostRepository.java: Added new methods findByTitle, findByFirstName, and findByLink to allow searching posts by title, first name, and link respectively.

Changes to the PostTest class:

• src/test/java/com/liatrio/dojo/devopsknowledgeshareapi/PostTest.java: Added new test cases to validate the new dateUpdated field in the Post class, the link validation logic, and the date format. [1] [2]