Define "Update" test scenario implementation details

[ezgidemirel]

Update scenario is harder to test due to some conditions we need to satisfy. To update a resource, we need to find a
mutable field and set a proper value. Terraform provider metadata has mutable fields and we may use this information to generate a second example manifest to test update scenarios. Please note that, while generating a second example manifest, we may hit some input validation issues. For these kinds of issues, we may use a configuration framework that allows developers to set some mutable field values.

Another alternative we can use is updating fields like tags and labels whenever a resource has them. As stated in
this Tagging Convention Issue, roughly half of the resources have one of these fields. Even though it prevents the input validation issues and the work that needs to be done to generate a second manifest, the number of resources we can test may not be worth integrating into the testing pipeline.