ci(test): bump setup-python v5->v6 (fix Node 24 pip-cache stack overflow)

Author: Seungpyo1007

.github/workflows/test.yml

@@ -16,7 +16,7 @@ jobs:
           repository: GetTechAPI/TechAPI
           path: TechAPI
 
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@v6
         with:
           python-version: "3.12"
           cache: pip