chore(docs): Add changelog entry for May 19th

Author: gabrielmfern

apps/docs/changelog.mdx

@@ -6,6 +6,16 @@ description: "New features, bug fixes, and improvements made to each package."
 icon: "list-check"
 ---
 
+## May 19, 2025
+
+**React Email 4.0.15**
+
+- fix preview server's background gradient interferring with the user's colors
+
+**Create Email 1.2.1**
+
+- fix broken node 18 support
+
 ## May 16, 2025
 
 **React Email 4.0.14**