Use current Starlette middleware conventions

Signed-off-by: Ed Snible <snible@us.ibm.com>

Author: esnible

a2a/weather_service/src/weather_service/agent.py

@@ -215,14 +215,16 @@ def run():
     # Add tracing middleware - creates root span with MLflow/GenAI attributes
     app.add_middleware(BaseHTTPMiddleware, dispatch=create_tracing_middleware())
 
+    class LogAuthorizationMiddleware(BaseHTTPMiddleware):
+      async def dispatch(self, request, call_next):
+          auth_header = request.headers.get("authorization", "No Authorization header")
+          logger.info(
+              f"🔐 Incoming request to {request.url.path} with Authorization: {auth_header[:80] + '...' if len(auth_header) > 80 else auth_header}"
+          )
+          response = await call_next(request)
+          return response
+
     # Add logging middleware
-    @app.middleware("http")
-    async def log_authorization_header(request, call_next):
-        auth_header = request.headers.get("authorization", "No Authorization header")
-        logger.info(
-            f"🔐 Incoming request to {request.url.path} with Authorization: {auth_header[:80] + '...' if len(auth_header) > 80 else auth_header}"
-        )
-        response = await call_next(request)
-        return response
+    app.add_middleware(LogAuthorizationMiddleware)
 
     uvicorn.run(app, host="0.0.0.0", port=8000)