team.go: add support for private teams.

[lomkju]

What

Adds support for creating private teams in pagerduty.

Why

In accounts with advance permissions enabled the key default_role must be set in the request payload.
This package needs to be patched so that we can update the pagerduty provider which uses this package .
The payload key is not documented on the website, it was found using developer tools on the browser.
Setting default_role: none results in a private team.

Test cURL

curl --request POST \
  --url https://api.pagerduty.com/teams \
  --header 'Accept: application/vnd.pagerduty+json;version=2' \
  --header 'Authorization: Token token=xxxxxxxxxxxx' \
  --header 'Content-Type: application/json' \
  --data '{
  "team": {
    "type": "team",
    "name": "arjun-test",
    "description": "The engineering team",
    "default_role": "none"
  }
}'

Ref:

• https://developer.pagerduty.com/api-reference/2e80b2c79165e-create-a-team
• Support creation of private teams for accounts with advance permissions PagerDuty/terraform-provider-pagerduty#611

[johncoleman83]

@imjaroiswebdev , this LGTM. If you test out the API default_role is provided in the results of this API, and it is currently documented in the REST API docs as a valid request payload param. I suggest adding this as a lot of customers depend on private team and it is in the knowledge base docs here.

[imjaroiswebdev]

Hey @lomkju thank you! 🎉 This LGTM too @johncoleman83 thanks both for your contribution.