release prep for v1.40.0 (#822)

* release prep for v1.40.0

* Update CHANGELOG.md

---------

Co-authored-by: Brandon Croft <[email protected]>

Author: Uk1288

CHANGELOG.md

@@ -1,15 +1,15 @@
 # UNRELEASED
 
-## Enhancements
-* Adds a missing interface `WorkspaceResources` and the `List` method by @stefan-kiss [Issue#754](https://github.com/hashicorp/go-tfe/issues/754) 
- 
+# v1.40.0
+
 ## Bug Fixes
 * Removed unused field `AgentPoolID` from the Workspace model. (Callers should be using the `AgentPool` relation instead) by @brandonc [#815](https://github.com/hashicorp/go-tfe/pull/815)
 
 ## Enhancements
 * Add organization scope field for oauth clients by @Netra2104 [#812](https://github.com/hashicorp/go-tfe/pull/812)
 * Added BETA support for including `projects` relationship to oauth_client on create by @Netra2104 [#806](https://github.com/hashicorp/go-tfe/pull/806)
 * Added BETA method `AddProjects` and `RemoveProjects` for attaching/detaching oauth_client to projects by Netra2104 [#806](https://github.com/hashicorp/go-tfe/pull/806)
+* Adds a missing interface `WorkspaceResources` and the `List` method by @stefan-kiss [Issue#754](https://github.com/hashicorp/go-tfe/issues/754) 
 
 # v1.39.2