[umbraco] Add 15.0 release (#6280)

Author: ziceck

products/umbraco.md

@@ -37,6 +37,13 @@ auto:
 #
 # Support and EOL dates are documented on https://umbraco.com/products/knowledge-center/long-term-support-and-end-of-life/.
 releases:
+-   releaseCycle: "15"
+    releaseDate: 2024-11-14
+    eoas: 2025-08-14
+    eol: 2025-11-14
+    latest: '15.0.0'
+    latestReleaseDate: 2024-11-14
+
 -   releaseCycle: "14"
     releaseDate: 2024-05-30
     eoas: 2025-03-02