bump-cs-version missed eclipsecs-sevntu-plugin

[rnveach]

Identified at
https://github.com/sevntu-checkstyle/sevntu.checkstyle/blob/master/eclipsecs-sevntu-plugin/pom.xml#L31
from commit 3fd8268

This was a new addition at 220bf2a due to a reported bug and was missed being added to bump-cs-version before its next run which resulted in the missed change at location mentioned above.

The main point of this issue is to expand bump-cs-version.yml for the new area to bump the checkstyle version when the YML is run. The above POM can also be updated as part of this issue in a separate commit.

https://github.com/sevntu-checkstyle/sevntu.checkstyle/blob/master/.github/workflows/bump-cs-version.yml

[rnveach]

@romani If you agree, I think @stoyanK7 can work on this as part of the project

[romani]

Issue is created checkstyle/contribution#694

[romani]

Fix is merged