push all changes to a bot node at once in event jobs

[beckermr]

The bot has been encountering missing pr_info and version_pr_info blob errors. I think this may happen when a new feedstock is made.

Currently for a new feedstock, the bot event job pushes the pr_info and version_pr_info blobs first via the github api. Then it pushes the node attributes blob.

The logic had been that github would honor the API requests in order.

However, I suspect sometimes things get out of order on the github backend.

To ensure transaction-like semantics, we should push all of the files at once in a single API call via a pattern like this stackoverflow post: https://stackoverflow.com/questions/61583403/edit-multiple-files-in-single-commit-with-github-api.