Update _config.yml

Author: ashmeet07

_config.yml

@@ -2,5 +2,5 @@ title: "Java Learning Platform"
 description: "Learn Java from Core to Senior level"
 baseurl: ""
 url: "https://ashmeet07.github.io/java-course"
-theme: minima  # Optional: Choose a Jekyll theme, you can use 'minima' or any other theme
+theme: jekyll-theme-cayman # You can choose any theme you like
 markdown: kramdown  # Ensure you're using kramdown for better Markdown rendering