Circle Ci updated their api and their response structure

[IvanGrigorov]

I tried to use the plugin and saw that the build failed in the CI because the checks for the Circle CI API were not correct any more.
I suggest the following change on these places. :)

[cla-bot]

Thank you for your pull request and welcome to our community. We could not parse the GitHub identity of the following contributors: Ivan Grigorov.
This is most likely caused by a git client misconfiguration; please make sure to:

1. check if your git client is configured with an email to sign commits git config --list | grep email
2. If not, set it up using git config --global user.email [email protected]
3. Make sure that the git commit email is configured in your GitHub account settings, see https://github.com/settings/emails