add datasource for policy_set

[Uk1288]

Description

Add datasource for policy set. This PR is in relation to the tfe_workspace_policy_set work here #591

Remember to:

• Update the Change Log

• Update the Documentation

Testing plan

Note: Policy set is a paid plan.

1. Create a policy set and then use datasource like:

data "tfe_policy_set" "readable_policy_set" {
  name = "my-policy-set"
  organization = "awesome-org"
}

External links

Include any links here that might be helpful for people reviewing your PR. If there are none, feel free to delete this section.

• Related PR

Output from acceptance tests

Please run applicable acceptance tests locally and include the output here. See TESTS.md to learn how to run acceptance tests.

If you are an external contributor, your contribution(s) will first be reviewed before running them against the project's CI pipeline.

$ TESTARGS="-run TestAccTFEWorkspace" make testacc

...

[laurenolivia]

@Uk1288, I was able to successfully reproduce this! ✅

I would recommend expanding your testing plan. Like in this case, a tester will not be able to successfully replicate the behavior without the following: a, b, c. And then add those to your testing plan. 😸

[sebasslash]

Looks good to me 🚀

[sebasslash]

Make sure you rebase once #602 is merged 👍 Disregard, I'll rebase your changes in #602

[sebasslash]

We can remove this since the API returns a 404 if the policy set is not found or the user is not authorized.

[Uk1288]

as per discussed, this will be added on next PR.

[Uk1288]

I have updated the test plan to indicate that policy sets is a paid plan. I am not sure what the comment: to successfully replicate the behavior without the following: a, b, c means. Let's discuss.