chore(python): fix docs publish build (#777) Source-Link: https://github.com/googleapis/synthtool/commit/bd9ede2fea1b640b7e90d5a1d110e6b300a2b43f Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-python:latest@sha256:04c35dc5f49f0f503a306397d6d043685f8d2bb822ab515818c4208d7fb2db3a Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com> Co-authored-by: Anthonios Partheniou <[email protected]>