Add filter for group name

[TobseF]

I wanted to check only our updates for our internal dependencies.
Maybe I misunderstood the usage of the Ignore file. But I do not want to declare all our 600 dependencies in the ignore-file, just to check updates for our 15 internal ones with the group name prefix de.companyname.

This is why I added a filter param to MvnCheck.
This allows filtering the artifact group by a regular expression.

Here is an example of how to only search for an artifact
with the group name suffix com.github.alexisjehan:

- filter com.github.alexisjehan.*

I'm happy for any feedback and suggestions.
Maybe it would be good to also add some formatting hints to the project, so I won't destroy the code format with my merge request.

[AlexisJehan]

Thank you for your contribution!

I have started to work on the refactor of ArtifactFilter to improve the reusability for both usages (ignore files and the new filter parameter).
In addition, I think I will improve ignore files by allowing patterns not only for versions, but also for group ids and artifact ids (that will work for the new filter parameter too).

[TobseF]

I'm very happy to hear that you adapt my additional filter option. After using it, I also mentioned that your glob-based filter is a better option, than my regex. So I stay tuned for the result, so don't need a special build for our project anymore.

[AlexisJehan]

Released in 1.7.0.