Modify link_text and links in header.yaml

Updated link_text and links for various Zoomcamp courses.

Author: alexeygrigorev

_data/header.yaml

@@ -1,16 +1,12 @@
 announcement:
+  link_text: "Register here!"
   # text: "Machine Learning Zoomcamp: Free ML Engineering course."
-  # link_text: "Register here!"
   # link: "http://mlzoomcamp.com"
   # text: "Data Engineering Zoomcamp: Free Data Engineering course."
-  # link_text: "Register here!"
   # link: "https://github.com/DataTalksClub/data-engineering-zoomcamp"
   # text: "MLOps Zoomcamp: Free MLOps course."
-  # link_text: "Register here!"
-  link: "https://github.com/DataTalksClub/mlops-zoomcamp"
+  # link: "https://github.com/DataTalksClub/mlops-zoomcamp"
   text: "LLM Zoomcamp: Free LLM engineering course."
-  link_text: "Register here!"
-  # link: "https://github.com/DataTalksClub/llm-zoomcamp"
+  link: "https://github.com/DataTalksClub/llm-zoomcamp"
   # text: "AI Dev Tools Zoomcamp: Learn AI-powered coding assistants and agents"
-  # link_text: "Register here!"
   # link: "https://airtable.com/appJRFiWKHBgmEt70/shrpw7rk55Ewr1jCG"