Upgrade Fern version from 3.48.2 to 4.15.5

Co-Authored-By: jon <jon@buildwithfern.com>

Author: devin-ai-integration[bot]

fern/fern.config.json

@@ -1,4 +1,4 @@
 {
   "organization": "plantstore",
-  "version": "3.48.2"
+  "version": "4.15.5"
 }