📝 Update source examples and docs from Python 3.9 to 3.10 (#14900)

docs_src/behind_a_proxy/tutorial004_py310.py

@@ -0,0 +1,15 @@
+from fastapi import FastAPI, Request
+
+app = FastAPI(
+    servers=[
+        {"url": "https://stag.example.com", "description": "Staging environment"},
+        {"url": "https://prod.example.com", "description": "Production environment"},
+    ],
+    root_path="/api/v1",
+    root_path_in_servers=False,
+)
+
+
+@app.get("/app")
+def read_main(request: Request):
+    return {"message": "Hello World", "root_path": request.scope.get("root_path")}