Auth0: Grant EasyCLA M2M client access to SSS audience

[mlehotskylf]

Parent: #4985

Repo for the work: linuxfoundation/auth0-terraform

Context

EasyCLA needs a client_credentials grant to call the Sanctions Screening Service (SSS). The SSS Auth0 API (resource server) was created in auth0-terraform PR #260.

What to do

Add a client grant for the EasyCLA M2M client to the SSS audience in each environment:

Env	SSS Audience
Dev	https://sanctions-screening.dev.v2.cluster.linuxfound.info/
Staging	https://sanctions-screening.staging.v2.cluster.linuxfound.info/
Prod	https://sanctions-screening.lfx.linuxfoundation.org/

Acceptance criteria

• EasyCLA M2M client can obtain a token with the SSS audience in dev
• Same for staging and prod
• Client ID and secret are available in the environment where EasyCLA can read them

Blocks: #4985 child tickets (SSS client + CCLA/ECLA integration)