Add attributes containing commas to the yaml file

[MorganReid]

Here is the original test.yaml

This is the yaml I want to get

Now I want to add the property vault.hashicorp.com/agent-inject to the yaml file.I tried
yq '.spec.template.metadata.annotations + {"vault.hashicorp.com/agent-inject":"true"}' -i test.yaml , nothing changes in the file.
I tried
yq '.spec.template.metadata.annotations.vault.hashicorp.com/agent-inject="true"' -i test.yaml ,The output is not what I want

how should I write it?

[MorganReid]

Has been resolved. use
yq '.spec.template.metadata.annotations.["vault.hashicorp.com/agent-inject"]="true"' -i test.yaml