Add subscribe link to header

config/header.md

@@ -19,4 +19,12 @@
 
 This curated list contains {project_count} awesome open-source projects with a total of {stars_count} stars grouped into {category_count} categories. All projects are ranked by a project-quality score, which is calculated based on various metrics automatically collected from GitHub and different package managers. If you like to add or update projects, feel free to open an [issue](https://github.com/ml-tooling/best-of-ml-python/issues/new/choose), submit a [pull request](https://github.com/ml-tooling/best-of-ml-python/pulls), or directly edit the [projects.yaml](https://github.com/ml-tooling/best-of-ml-python/edit/main/projects.yaml). Contributions are very welcome!
 
-> 🧙‍♂️ Create your own best-of list in just 3 minutes with [this guide](https://github.com/best-of-lists/best-of/blob/main/create-best-of-list.md).
+---
+
+<p align="center">
+    📫&nbsp; Subscribe to our <a href="https://mltooling.substack.com/subscribe">weekly newsletter</a> for updates on the best machine-learning libraries and tools.<br>
+    <i>Get notified on trending projects, new additions, detailed comparisons, and more!</i>
+</p>
+
+---
+