feat: add `gcf-owl-bot[bot]` to `ignoreAuthors`

[yoshi-automation]

This PR was generated using Autosynth. :rainbow:

Synth log will be available here: https://source.cloud.google.com/results/invocations/00d271af-f95c-45b1-89db-4a1ec8c1dbff/targets

• [ ] To automatically regenerate this PR, check this box. (May take up to 24 hours.)

Source-Link: https://github.com/googleapis/synthtool/commit/7332178a11ddddc91188dc0f25bca1ccadcaa6c6

[generated-files-bot[bot]]

Warning: This pull request is touching the following templated files:

• .github/generated-files-bot.yml - .github/generated-files-bot.(yml|yaml) should be updated in synthtool