(it's a space instead of

=

)

You're also only setting 1 config value so you could use

pulumi config set

instead of

set-all

It also looks like you might need some quote marks around those strings in the config value? I'm not as sure about that. Like

[{"zone": "us-central1-a", "quantity": 3}, {"zone": "us-central1-b", "quantity": 1}]