StackSources

[brandonc]

Description

Adds BETA support for StackSources and Organization StacksEnabled attribute

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.

$ OAUTH_CLIENT_GITHUB_TOKEN=$GITHUB_TOKEN ENABLE_BETA=1 go test ./... -v -run "TestStackSourceCreateUploadAndRead"
?   	github.com/hashicorp/go-tfe/examples/backing_data	[no test files]
?   	github.com/hashicorp/go-tfe/examples/configuration_versions	[no test files]
?   	github.com/hashicorp/go-tfe/examples/organizations	[no test files]
?   	github.com/hashicorp/go-tfe/examples/registry_modules	[no test files]
?   	github.com/hashicorp/go-tfe/examples/run_errors	[no test files]
?   	github.com/hashicorp/go-tfe/examples/state_versions	[no test files]
?   	github.com/hashicorp/go-tfe/examples/users	[no test files]
?   	github.com/hashicorp/go-tfe/examples/workspaces	[no test files]
?   	github.com/hashicorp/go-tfe/mocks	[no test files]
=== RUN   TestStackSourceCreateUploadAndRead
    stack_source_integration_test.go:61: Found stack source configuration-- ID "stc-WzMCg22VuAj1zBop"
--- PASS: TestStackSourceCreateUploadAndRead (6.31s)
PASS
ok  	github.com/hashicorp/go-tfe	6.817s

[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.