More descriptive error message by including offending group name

[nhomble]

More descriptive error message by including offending group name

[nhomble]

I am not totally sure what is the cause of

Expected feature release number in range of 9 to 15, but got: 8

but apparently other prs are seeing the same issue. If there is a setting I messed up, please let me know and I will remember on future prs!

[liry]

@nhomble the problem is with already unsupported setup of Travis builds:

spring-shell/.travis.yml

Line 7 in 296db93

- oraclejdk8

The fix is here: #317

... but worse problem for this repo is that there seems to be no maintainer merging PRs and releasing new versions :(

[nhomble]

ah thanks @liry that makes sense, and yeah it's a shame I don't see any activity in this repo anymore