chore: Add license headers for python config files (#167)

Source-Author: Anthonios Partheniou <partheniou@google.com>
Source-Date: Tue Apr 6 11:32:03 2021 -0400
Source-Repo: googleapis/synthtool
Source-Sha: 5b5bf6d519b2d658d9f2e483d9f6f3d0ba8ee6bc
Source-Link: https://github.com/googleapis/synthtool/commit/5b5bf6d519b2d658d9f2e483d9f6f3d0ba8ee6bc
3 files changed