Fix the build: fix test for newer numpy

[lopuhin]

Exception message is different now:

IndexError: index 5 is out of bounds for axis 0 with size 2

while it used to be:

IndexError: index 5 is out of bounds for axis 1 with size 2

the new one makes more sense, as this is a 1d-array.

[codecov-io]

Codecov Report

Merging #295 into master will increase coverage by 4.96%. The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #295      +/-   ##
==========================================
+ Coverage   92.29%   97.25%   +4.96%     
==========================================
  Files          44       44              
  Lines        2841     2841              
  Branches      539      539              
==========================================
+ Hits         2622     2763     +141     
+ Misses        178       41     -137     
+ Partials       41       37       -4

Impacted Files	Coverage Δ
eli5/utils.py	98.79% <ø> (ø)	:arrow_up:
eli5/sklearn/unhashing.py	96.95% <0%> (+1.21%)	:arrow_up:
eli5/xgboost.py	99.39% <0%> (+1.21%)	:arrow_up:
eli5/lime/utils.py	86.48% <0%> (+1.35%)	:arrow_up:
eli5/sklearn/utils.py	90.14% <0%> (+1.4%)	:arrow_up:
eli5/formatters/text.py	99.19% <0%> (+1.61%)	:arrow_up:
eli5/lime/lime.py	97% <0%> (+2%)	:arrow_up:
eli5/formatters/html.py	100% <0%> (+3.63%)	:arrow_up:
eli5/_feature_names.py	94.54% <0%> (+4.54%)	:arrow_up:
eli5/base_utils.py	100% <0%> (+10%)	:arrow_up:
... and 4 more

[kmike]

Thanks @lopuhin!