Add missing plugin to Zod plugin example

[gustafc]

Without pluginTs, you get the following error running kubb generate if you copy/paste the example:

 ERROR  This plugin has a pre set that is not valid([               
  "plugin-oas",
  "plugin-ts"
]) (plugin: plugin-oas, hook: buildStart) (plugin: plugin-oas, hook: buildStart)

[changeset-bot]

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Latest commit: f2cf55b

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