Updating the gpg key for packages.nginx.org

[mathijswesterhof]

This is a pull-request to solve issue 96

[eramos-ce]

I tested this locally, and the build works perfectly now. However, there is an issue starting unitd when the container starts.

I found that that the regextester/start.sh needs to be updated as follows:

unitd --modulesdir /usr/lib/unit/modules/ --log /var/log/unit.log

Should that be a separate issue, and fixed on a separate pull request?

[mathijswesterhof]

I've updated the merge request, I think it's logical to include this to make the regex-tester working properly again

[lucacome]

Thanks @mathijswesterhof !