Update astropy to 4.0.2 to fix fits 1d issue

[maxnoe]

No description provided.

[codecov]

Codecov Report

Merging #102 into master will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #102      +/-   ##
==========================================
- Coverage   89.20%   89.18%   -0.02%     
==========================================
  Files          36       36              
  Lines        1195     1193       -2     
==========================================
- Hits         1066     1064       -2     
  Misses        129      129              

Impacted Files	Coverage Δ
pyirf/tests/test_eventdisplay_comparison.py	100.00% <100.00%> (ø)
pyirf/version.py	100.00% <100.00%> (ø)

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[HealthyPear]

We should also remove any related material from the code, e.g. in the integration test we have code checking the rows dimentionality in the HDUs that will become stale with these changes.

[maxnoe]

Ok, I removed the "ignored_errors" part in the integration test as these are now expected to pass and they do