Feature request: Consume API Key from environment variable

[Yann-P]

Hello,

I am currently authenticating calls this way:

const api = new mergeAPI.CandidatesApi()
api.defaultHeaders = {
  Authorization: 'Bearer ' + process.env.MERGE_API_KEY,
}

const res = await api.candidatesList('TEST_ACCOUNT_TOKEN')
// ...

It would be handy if the SDK could directly consume an environment variable without having to configure the authentication at every API class insantiation