Fix ignored json meta tags for run variables in RunCreateOptions

[Uk1288]

Description:

**NOTE: TheVariables field in Run has been changed from type []*RunVariable to []*RunVariableAttr **

Ref PR: #204

Run variables in RunCreateOptions are not marshalled in line with the API (https://www.terraform.io/cloud-docs/api-docs/run#request-body). The variables are currently marshalled as:

"variables": [
        {
          "Key": "aKey",
          "Value": "\"aValue\""
        }
]

instead of

"variables": [
        {
          "key": "aKey",
          "value": "\"aValue\""
        }
]

This PR adds changes that marshals and un-marshals the run variables correctly.

Testing plan

1. Create a run with options

	newRun, err := client.Runs.Create(context.Background(), tfe.RunCreateOptions{
		Workspace: &tfe.Workspace{
			ID: "ws-ID",
		},
		Variables: []*tfe.RunVariableOption{
			{
				Key:   "name",
				Value: "\"aName\"",
			},
		},
	})

1. Run should be created with correct variable key, name attributes,
2. Run value in go client should have Key, Value fields populated as well.

External links

• API documentation
• Issue

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.

$ TFE_ADDRESS="https://example" TFE_TOKEN="example" TF_ACC="1" go test ./... -v -tags=integration -run TestRunCreateOptions_Marshal

=== RUN   TestRunCreateOptions_Marshal
--- PASS: TestRunCreateOptions_Marshal (1.47s)
PASS
ok 

[brandonc]

Would it bet better to just redefine the RunVariable struct to be decorated as json: instead of jsonapi: ? I think that was the intent and it just got decorated incorrectly. By me, probably!

[Uk1288]

I initially tried redefining the RunVariable, in that case it will marshal correctly from Go value to json but un-marshalling from json to Go value stops working. The only way I found to make both direction work is if I create the two distinct types.

[brandonc]

Yeah, I see what you mean, now. Since RunVariable was used as a create option, which more often times requires callers to specify the exact type name (example), I think it would be better to redefine that as "json:" and create a new type for use in the Run struct. Like this WDYT?

I think then we could get away with not reving the major version... Although we should still note this type change in the release notes in the context of a bug fix.

[Uk1288]

Yes, this makes sense. I have renamed attributes to RunVariable and RunVariableAttr. This way all existing Create run calls will still work.

[annawinkler]

If this is a breaking change, is this a major version bump then?
cc @brandonc

[brandonc]

@annawinkler It's not a breaking change because the behavior doesn't match the documentation. (It capitalizes the keys in the request, which technically works but it's not expected) So this is just a bug fix.

[brandonc]

@annawinkler I see now that you mean modifying the actual type. Let me think about it. It would probably be less impactful to add a new output type and redefine the existing input type.

[brandonc]

Don't forget to add CHANGELOG

[laurenolivia]

Hmm looks like StateVersion is flaking on your PR 🤔 But I checked out this branch and you have the latest changes.

[laurenolivia]

Testing plan works as expected! ✅

[brandonc]

Let's mention the type that changed as well.

[annawinkler]

Nice! 🌟

[annawinkler]

[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.