docs: fix OS string typo in RTD YML

Author: sr-murthy

.readthedocs.yaml

@@ -7,7 +7,7 @@ version: 2
 
 # Set the OS, Python version and other tools you might need
 build:
-  os: ubuntu-latest
+  os: ubuntu-lts-latest
   tools:
     python: "3.14"