Read the configuration file form PR branch

[rlaverde]

Reading the .pep8speaks.yaml file from PR branch instead of base branch, will make easy to test changes in the config file.

[OrkoHunter]

Hello @rlaverde

Thanks for opening an issue about it. The default behavior for reading the config file was to read it from the PR branch (like Travis, and others) itself. It was working fine, when suggestions brought up some issues -

1. If there were multiple Pull Requests pending, all of them had to be rebased, just to ignore some errors.
2. Same goes for a change every time. Changing it on the main repo will instantly reflect on old/new PRs.

Hence, a month ago the behavior was changed.

[rlaverde]

I understood, maybe the PR branch could be a fallback if the there isn't a config file in the main branch. Or maybe and option mentioning the bot, i. e. "@pep8speaks read config from PR branch".

[OrkoHunter]

Thank you @rlaverde for your suggestion! PEP8Speaks will now look at the branch of Pull Request as a fallback if no config is found on the base branch.