Added operation calls for authenticating and fetching authentication …

…providers

Update the ruby client to come into line with the v2 api for authenticating with OIDC, and adding the ability to hit the new OIDC providers endpoint.

Describe how the desired outcome above has been achieved with this PR. In particular, consider:

What's changed? Why were these changes made?
How should the reviewer approach this PR, especially if manual tests are required?
Are there relevant screenshots you can add to the PR description?

Resolves #[relevant GitHub issue(s), e.g. 76]

CyberArk internal issue link: ONYX-20676

At least 1 todo must be completed in the sections below for the PR to be merged.

[x] The CHANGELOG has been updated, or
[ ] This PR does not include user-facing changes and doesn't require a CHANGELOG update

[x] This PR includes new unit and integration tests to go with the code changes, or
[ ] The changes in this PR do not require tests

[ ] Docs (e.g. READMEs) were updated in this PR
[ ] A follow-up issue to update official docs has been filed here: [insert issue ID]()
[ ] This PR does not require updating any documentation

[ ] This PR changes product behavior and has been reviewed by a PO, or
[x] These changes are part of a larger initiative that will be reviewed later, or
[ ] No behavior was changed with this PR

[ ] Security architect has reviewed the changes in this PR,
[x] These changes are part of a larger initiative with a separate security review, or
[ ] There are no security aspects to these changes

cyberark / conjur-api-ruby