Enhance README with newsletter subscription details

Added a newsletter subscription section with insights on AWS infrastructure.

Author: AnastasiaFilatova

README.md

@@ -1,4 +1,15 @@
-[![FivexL](https://releases.fivexl.io/fivexlbannergit.jpg)](https://fivexl.io/)
+[![FivexL](https://releases.fivexl.io/fivexlbannergit_new.png)](https://fivexl.io/#email-subscription)
+
+### Want practical AWS infrastructure insights?
+
+👉 [Subscribe to our newsletter](https://fivexl.io/#email-subscription) to get:
+
+- Real stories from real AWS projects  
+- No-nonsense DevOps tactics  
+- Cost, security & compliance patterns that actually work  
+- Expert guidance from engineers in the field
+
+=========================================================================
 
 # AWS EC2 Spot Price Terraform module
 An easy way to get the best Spot price to control costs.