Set stack outputs on migrate

[hhashimoto]

Because Object.keys(outputs).length < 60 on
lib/util.js#stackHasRoom always returns true.

[dougmoscrop]

Can you add a test? I'm surprised why this happens, because all outputs are supposed to be rewritten with their migrated ones:

https://github.com/dougmoscrop/serverless-plugin-split-stacks/blob/master/lib/replace-outputs.js#L6

In fact this way seems like it would lose outputs?

[hhashimoto]

stack.Outputs are added by lib/util.js#nestedOutput
https://github.com/dougmoscrop/serverless-plugin-split-stacks/blob/master/lib/utils.js#L84

and called lib/util.js#stackHasRoom before lib/util.js#nestedOutput
https://github.com/dougmoscrop/serverless-plugin-split-stacks/blob/master/split-stacks.js#L60

    return Promise.resolve()
      .then(() => this.setDeploymentBucketEndpoint())
      .then(() => this.migrateExistingResources()) // Call lib/util.js#stackHasRoom
      .then(() => this.migrateNewResources()) // Call lib/util.js#stackHasRoom
      .then(() => this.replaceReferences()) // Call lib/util.js#nestedOutput
      .then(() => this.replaceOutputs()) // Call lib/util.js#nestedOutput
      .then(() => this.replaceConditions())
      .then(() => this.mergeStackResources())
      .then(() => this.sequenceStacks())
      .then(() => this.writeNestedStacks())
      .then(() => this.logSummary());

then stack.Outputs is always {} whenever called lib/util.js#stackHasRoom
https://github.com/dougmoscrop/serverless-plugin-split-stacks/blob/master/lib/utils.js#L193