[TF-9914] Add auto destroy attribute to workspaces

[notchairmk]

Description

Updates Workspaces to include the AutoDestroyAt attribute. This attribute is settable on create and update.

Adds a Time receiver to the existing type helpers.
Adds an Nullable generic type with custom marshaling to allow updates to attributes which use significant null values, but which also require omitempty behavior.

Testing plan

Updated workspace integration tests

External links

• API documentation

Output from tests

Including output from tests may require access to a TFE instance. Ignore this section if you have no environment to test against.

PASS TestWorkspacesUpdate/with_valid_options (0.28s)
      --- PASS: TestWorkspacesUpdate/with_valid_options (0.28s)
PASS TestWorkspacesCreate/with_valid_options (0.34s)
      --- PASS: TestWorkspacesCreate/with_valid_options (0.34s)

[nfagerlund]

I have questions about this one before I can approve it! (And if there's good answers already, I'll probably push to get them into docs for this attribute.)

From a glance at the workspace api docs, it seems this is a field where a string value means auto-destroy is turned on (with the value of the string being the deadline), but a null value means auto-destroy is turned OFF.

I presume this is why the field on the Workspace struct is a *time.Time pointer instead of a value like the other times!

But: how do I turn auto-destroy off for a workspace?

In the CreateOptions / UpdateOptions structs, you've set the field to omitempty for the serializer, so would a nil pointer do nothing? It seems like it might be impossible to turn it off once it's turned on.

I haven't tested this yet! If I'm wrong, please add a new integration test demonstrating turning auto-destroy on and off again.

[notchairmk]

Removed omitempty from create and update options (probably don't need to remove it from the create options, but I personally don't have strong feelings one way or the other). I'm not sure if the current implementation works against the grain for patterns elsewhere in the repo, so definitely looking for feedback.

[notchairmk]

it seems like there are maybe two ways that I can think of to do this (also open to suggestions):

1. add to existing update options without omitempty. this is the first implementation, but has the side effect of potentially allowing the user to unintentionally unset AutoDestroyAt
2. create a distinct remove action, allow omitempty on create and update options. this feels like the preferred path.

let me know if there's another route we should take.

to fix linting I'd probably break the Sprintf calls for "organizations/%s/workspaces/%s" into their own func. but will hold off until I hear further

[sebasslash]

This pretty much has my approval pending updating the changelog entry. Comments with 💅 are entirely optional.

Really nice work 🔥

[github-actions]

Reminder to the contributor that merged this PR: if your changes have added important functionality or fixed a relevant bug, open a follow-up PR to update CHANGELOG.md with a note on your changes.