Remove beta references from docs

Author: mkam

CHANGELOG.md

@@ -1,7 +1,7 @@
 ## Unreleased
 
 FEATURES:
-* `r/tfe_variable_set`: Add `parent_project_id` attribute, which is a beta feature and is not available to all users, by @mkam [#1522](https://github.com/hashicorp/terraform-provider-tfe/pull/1522)
+* `r/tfe_variable_set`: Add `parent_project_id` attribute, by @mkam [#1522](https://github.com/hashicorp/terraform-provider-tfe/pull/1522)
 
 ## v0.61.0
 

website/docs/d/variable_set.html.markdown

@@ -38,4 +38,4 @@ The following arguments are supported:
 * `workspace_ids` - IDs of the workspaces that use the variable set.
 * `variable_ids` - IDs of the variables attached to the variable set.
 * `project_ids` - IDs of the projects that use the variable set.
-* `parent_project_id` - ID of the project that owns the variable set. This feature is currently in beta and is not available to all users.
+* `parent_project_id` - ID of the project that owns the variable set.

website/docs/r/variable_set.html.markdown

@@ -139,7 +139,7 @@ The following arguments are supported:
   Must not be set if `global` is set. This argument is mutually exclusive with using the resource
   [tfe_workspace_variable_set](workspace_variable_set.html) which is the preferred method of associating a workspace
   with a variable set.
-* `parent_project_id` - (Optional) ID of the project that should own the variable set. If set, than the value of `global` must be `false`. This feature is currently in beta and is not available to all users.
+* `parent_project_id` - (Optional) ID of the project that should own the variable set. If set, than the value of `global` must be `false`.
 
 ## Attributes Reference