Update disk setup step to use context manager

Signed-off-by: brianherrera <briher@amazon.com>

scripts/build/bootstrap/incremental_build_util.py

@@ -326,7 +326,7 @@ def mount_volume_to_device(created):
         # Some Windows configs will automatically set new drives as online causing diskpart setup script to fail.
         offline_drive()
 
-        f = tempfile.NamedTemporaryFile(delete=False)
+        with tempfile.NamedTemporaryFile(delete=False) as f:
             f.write("""
             select disk 1
             online disk
@@ -342,8 +342,6 @@ def mount_volume_to_device(created):
             active
             """.encode('utf-8'))
 
-        f.close()
-
         subprocess.call(['diskpart', '/s', f.name])
 
         time.sleep(5)