Fix failing S3 tests by reverting upgrade of GCS client lib to 1.19.0 (#4256)
Fix failing S3 tests by reverting upgrade of GCS client lib to 1.19.0 (#4256)


(cherry picked from commit f6107b44646ed8466c99dd23920598e97622a241)

michalkurka/h2o-3,h2oai/h2o-3,michalkurka/h2o-3,michalkurka/h2o-3,h2oai/h2o-3,h2oai/h2o-3,h2oai/h2o-3,michalkurka/h2o-3,michalkurka/h2o-3,michalkurka/h2o-3,h2oai/h2o-3,h2oai/h2o-3,h2oai/h2o-3,h2oai/h2o-3,michalkurka/h2o-3