Add OPA support for Policy Set API's

[mrinalirao]

Description

Add OPA support to the go-tfe client for policy sets. OPA is still in beta phase.
This PR only contains changes to the policy set API's.

For a complete list of API's that will be updated in subsequent PRs see : https://github.com/hashicorp/terraform-docs-common/pull/141/files

Api's updated:

• Policy set creation (Adds kind + overridable attribute)
• List Policy sets (Adds filter by kind support)

Testing plan

Integration tests added

External links

• API Docs
• JIRA
• API PR

Output from tests

Needs the following env vars:
TFE_ADDRESS
TFE_TOKEN
OAUTH_CLIENT_GITHUB_TOKEN
GITHUB_POLICY_SET_IDENTIFIER
Set ENABLE_BETA=1

envchain local go test -run TestPolicySetsCreate_Beta -v ./... -tags=integration
=== RUN   TestPolicySetsCreate_Beta
=== RUN   TestPolicySetsCreate_Beta/with_valid_attributes
=== RUN   TestPolicySetsCreate_Beta/with_kind_missing
=== RUN   TestPolicySetsCreate_Beta/with_all_attributes_provided_-_sentinel
=== RUN   TestPolicySetsCreate_Beta/with_all_attributes_provided_-_OPA
=== RUN   TestPolicySetsCreate_Beta/with_missing_overridable_attribute
=== RUN   TestPolicySetsCreate_Beta/with_policies_and_workspaces_provided
=== RUN   TestPolicySetsCreate_Beta/with_vcs_policy_set
=== RUN   TestPolicySetsCreate_Beta/with_vcs_policy_updated
=== RUN   TestPolicySetsCreate_Beta/without_a_name_provided
=== RUN   TestPolicySetsCreate_Beta/with_an_invalid_name_provided
=== RUN   TestPolicySetsCreate_Beta/without_a_valid_organization
--- PASS: TestPolicySetsCreate_Beta (22.10s)
    --- PASS: TestPolicySetsCreate_Beta/with_valid_attributes (0.59s)
    --- PASS: TestPolicySetsCreate_Beta/with_kind_missing (0.59s)
    --- PASS: TestPolicySetsCreate_Beta/with_all_attributes_provided_-_sentinel (1.04s)
    --- PASS: TestPolicySetsCreate_Beta/with_all_attributes_provided_-_OPA (0.57s)
    --- PASS: TestPolicySetsCreate_Beta/with_missing_overridable_attribute (0.56s)
    --- PASS: TestPolicySetsCreate_Beta/with_policies_and_workspaces_provided (3.13s)
    --- PASS: TestPolicySetsCreate_Beta/with_vcs_policy_set (4.98s)
    --- PASS: TestPolicySetsCreate_Beta/with_vcs_policy_updated (5.02s)
    --- PASS: TestPolicySetsCreate_Beta/without_a_name_provided (0.00s)
    --- PASS: TestPolicySetsCreate_Beta/with_an_invalid_name_provided (0.00s)
    --- PASS: TestPolicySetsCreate_Beta/without_a_valid_organization (0.00s)
PASS
ok      github.com/hashicorp/go-tfe     23.067s
?       github.com/hashicorp/go-tfe/examples/organizations      [no test files]
?       github.com/hashicorp/go-tfe/examples/workspaces [no test files]
?       github.com/hashicorp/go-tfe/mocks       [no test files]

  envchain local go test -run TestPolicySetsList_Beta -v ./... -tags=integration
=== RUN   TestPolicySetsList_Beta
=== RUN   TestPolicySetsList_Beta/without_list_options
=== RUN   TestPolicySetsList_Beta/with_pagination
=== RUN   TestPolicySetsList_Beta/with_search
=== RUN   TestPolicySetsList_Beta/with_include_param
=== RUN   TestPolicySetsList_Beta/filter_by_kind
=== RUN   TestPolicySetsList_Beta/without_a_valid_organization
--- PASS: TestPolicySetsList_Beta (13.14s)
    --- PASS: TestPolicySetsList_Beta/without_list_options (0.64s)
    --- PASS: TestPolicySetsList_Beta/with_pagination (0.57s)
    --- PASS: TestPolicySetsList_Beta/with_search (0.61s)
    --- PASS: TestPolicySetsList_Beta/with_include_param (1.06s)
    --- PASS: TestPolicySetsList_Beta/filter_by_kind (0.65s)
    --- PASS: TestPolicySetsList_Beta/without_a_valid_organization (0.00s)
PASS
ok      github.com/hashicorp/go-tfe     13.306s
?       github.com/hashicorp/go-tfe/examples/organizations      [no test files]
?       github.com/hashicorp/go-tfe/examples/workspaces [no test files]
?       github.com/hashicorp/go-tfe/mocks       [no test files]

[annawinkler]

👋 Hi @mrinalirao ! Thank you for your contribution! It looks like this PR might be targeting a feature that is in beta. We have guidance in our docs about how to add tests for beta features, plus how to comment when a feature is in beta. Could you please update the PR based on that guidance? 💖

I'll take a more detailed look and add more thoughts ✨

[glennsarti]

One typo change but should not block this PR.

[glennsarti]

Almost forgot. You'll need a Changelog entry for this.

[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.