Duplicate comments when using bot account

[flugg]

We have an issue where we want our organization bot account to be responsible for making the comment on the pull request. This can easily be done by changing the repo-token. However, there's a check in the code checking if the comment is posted by a bot user (https://github.com/preactjs/compressed-size-action/blob/master/src/index.js#L202). Regular bot accounts are not marked as bots, so this fails, and instead of updating the existing comment it instead posts a new.

The other check should be sufficient enough. Would you accept a PR that removes the bot-check?

Best regards