test: increase limits to fix ray cluster issues in upgrade tests (#854)

Author: pawelpaszki

tests/upgrade/raycluster_sdk_upgrade_test.py

@@ -50,12 +50,12 @@ def run_mnist_raycluster_sdk_oauth(self):
                 num_workers=1,
                 head_cpu_requests=1,
                 head_cpu_limits=1,
-                head_memory_requests=4,
-                head_memory_limits=4,
+                head_memory_requests=6,
+                head_memory_limits=8,
                 worker_cpu_requests=1,
                 worker_cpu_limits=1,
-                worker_memory_requests=4,
-                worker_memory_limits=4,
+                worker_memory_requests=6,
+                worker_memory_limits=8,
                 image=ray_image,
                 write_to_file=True,
                 verify_tls=False,