fix: use fern python SDK generator v4.55.5 compatible with CLI v3.62.0

v4.64.1 requires Fern CLI v3.72.0+ but this repo uses v3.62.0. Use v4.55.5
which is the latest version compatible with the current CLI and still includes
the fix for duplicate field names in discriminated union types (v4.41.8).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Vapi Tasker

fern/apis/api/generators.yml

@@ -11,7 +11,7 @@ groups:
   python-sdk:
     generators:
       - name: fernapi/fern-python-sdk
-        version: 4.64.1
+        version: 4.55.5
         api:
           settings:
             prefer-undiscriminated-unions-with-literals: true