feat: switch to null buildpack for performance

tests/apps/python/web.py

@@ -0,0 +1,17 @@
+import http.server
+import os
+
+
+class GetHandler(http.server.BaseHTTPRequestHandler):
+    def do_GET(self):
+        self.send_response(200)
+        self.send_header("Content-Type", "text/plain; charset=utf-8")
+        self.end_headers()
+        self.wfile.write("python/http.server".encode("utf-8"))
+
+
+if __name__ == "__main__":
+    port = int(os.getenv("PORT", 5000))
+    server = http.server.HTTPServer(("0.0.0.0", port), GetHandler)
+    print("Listening on port {0}".format(port))
+    server.serve_forever()