feat: add GCP auth variant

mentioned in commit bcedc68c

mentioned in merge request Orange-OpenSource/lfn/ci_cd/chained-ci-py!252 (merged)

mentioned in merge request gaia-x/data-infrastructure-federation-services/deployment-scenario/catalogue/provider-catalogue!97 (merged)

mentioned in merge request gaia-x/data-infrastructure-federation-services/deployment-scenario/user-agent!50 (merged)

mentioned in merge request to-be-continuous/samples/python-docker-compose!2 (merged)

mentioned in merge request to-be-continuous/samples/python-on-azure!44 (merged)

mentioned in merge request to-be-continuous/samples/python-library!21 (merged)

mentioned in merge request to-be-continuous/samples/python-helmfile-on-kubernetes!69 (merged)

mentioned in merge request to-be-continuous/samples/python-on-kubernetes!58 (merged)

mentioned in merge request to-be-continuous/samples/python-serverless-on-aws!135 (merged)

mentioned in merge request gaia-x/data-infrastructure-federation-services/deployment-scenario/credential-generator!79 (closed)

mentioned in merge request gaia-x/data-infrastructure-federation-services/deployment-scenario/vc-issuer!34 (closed)

mentioned in merge request gaia-x/data-infrastructure-federation-services/deployment-scenario/credential-generator!87 (closed)

mentioned in merge request gaia-x/data-infrastructure-federation-services/deployment-scenario/vc-issuer!45 (closed)