fix(auth): accept PEM trust-chain preambles - #18555

fix(auth): accept PEM trust-chain preambles#18555

dhairyajangir wants to merge 2 commits into

googleapis:maingoogleapis/google-cloud-python:mainfrom

dhairyajangir:fix/auth-trust-chain-preambledhairyajangir/google-cloud-python:fix/auth-trust-chain-preambleCopy head branch name to clipboard