Support pkce_enbaled flag at auth0_connection option level

[abbaspour]

Auth0 now allows PKCE on oauth2 strategy. auth0_connection does not support it yet. This is how it would look like:

resource "auth0_connection" "connection" {
  name = "my-custom-social-connection"
  strategy = "oauth2"
  options {
    client_id = "XXXX"
    client_secret = "XXXX"
    authorization_endpoint = "https://example.com/authorize"
    token_endpoint = "https://example.com/token"
    scopes = ["scope1"]
    scripts = {
      fetchUserProfile = data.template_file.fetchUserProfile.rendered
    }
    pkce_enabled = true // <-- HERE
  }

  enabled_clients = [
    auth0_client.sample_client.id
  ]
}

[sergiught]

We have moved this issue over at auth0/terraform-provider-auth0#49 as this repo is now maintained at https://github.com/auth0/terraform-provider-auth0.