Add tests for vault

[VenelinMartinov]

pulumi/pulumi-terraform-bridge#1849

This PR adds tests for the following resources:

index_authbackend
index_policy
index_token
identity_group
generic_secret
github_team
github_authbackend

[github-actions]

Does the PR have any schema changes?

Looking good! No breaking changes found.
No new resources/functions.

Maintainer note: consult the runbook for dealing with any breaking changes.

[github-actions]

Is README.md missing any configuration options?

addAddressToEnv not found in Configuration section
authLogin not found in Configuration section
authLoginAws not found in Configuration section
authLoginAzure not found in Configuration section
authLoginCert not found in Configuration section
authLoginGcp not found in Configuration section
authLoginJwt not found in Configuration section
authLoginKerberos not found in Configuration section
authLoginOci not found in Configuration section
authLoginOidc not found in Configuration section
authLoginRadius not found in Configuration section
authLoginTokenFile not found in Configuration section
authLoginUserpass not found in Configuration section
caCertDir not found in Configuration section
caCertFile not found in Configuration section
clientAuth not found in Configuration section
headers not found in Configuration section
maxLeaseTtlSeconds not found in Configuration section
maxRetries not found in Configuration section
maxRetriesCcc not found in Configuration section
setNamespaceFromToken not found in Configuration section
skipChildToken not found in Configuration section
skipGetVaultVersion not found in Configuration section
skipTlsVerify not found in Configuration section
tlsServerName not found in Configuration section
vaultVersionOverride not found in Configuration section

Please add a description for each of these options to README.md. Details about them can be found in either the upstream docs or schema.json.