yq add array element with name and subfields

Question

I got this test.yaml:

volumes:
  - name: var-log
    hostPath:
      path: /var/log
  - name: dev-log
    hostPath:
      path: /dev/log

and want to achieve the following using Go yq - https://github.com/mikefarah/yq/

volumes:
  - name: var-log
    hostPath:
      path: /var/log
  - name: dev-log
    hostPath:
      path: /dev/log
  - name: sys
      mountPath: /sys

I cannot really get my head around it - with:

yq eval '.volumes |= (. + {"name":{"name":"sys"}})' test.yaml I got it almost, but the 3rd field name is missing (it should be name: sys but it is just name:)

volumes:
  - name: var-log
    hostPath:
      path: /var/log
  - name: dev-log
    hostPath:
      path: /dev/log
  - name:
      mountPath: /sys

I'm fiddling for some time now, but cannot get it working.