Rename deploy branch to deploy/rendezvous, fix Python SDK Go version

- Workflow trigger: release → deploy/rendezvous
- Python SDK: hardcoded go-version 1.21 → go-version-file: go.mod

Author: teovl

.github/workflows/deploy-rendezvous.yml

@@ -2,7 +2,7 @@ name: Deploy Rendezvous Server
 
 on:
   push:
-    branches: [release]
+    branches: [deploy/rendezvous]
   workflow_dispatch:
     inputs:
       rollback:

.github/workflows/publish-python-sdk.yml

@@ -189,7 +189,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v5
         with:
-          go-version: '1.21'
+          go-version-file: go.mod
 
       - name: Set up Python
         uses: actions/setup-python@v5