Replace usage of deprecated get_proj_coords_dask

[sfinkens]

pyresample.AreaDefinition.get_proj_coords_dask is deprecated. Use get_proj_coords(chunks=...) instead.

• Tests passed
• Passes git diff origin/master -- "*py" | flake8 --diff

[codecov]

Codecov Report

Merging #711 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #711      +/-   ##
==========================================
+ Coverage   79.99%   79.99%   +<.01%     
==========================================
  Files         147      147              
  Lines       21471    21472       +1     
==========================================
+ Hits        17176    17177       +1     
  Misses       4295     4295

Impacted Files	Coverage Δ
satpy/readers/utils.py	71.42% <100%> (+0.31%)	⬆️

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[coveralls]

Coverage increased (+0.0009%) to 79.997% when pulling fe5fc14 on sfinkens:get-proj-coords-dask-deprecated into ff45d3f on pytroll:master.

[coveralls]

Coverage increased (+0.0009%) to 79.997% when pulling fe5fc14 on sfinkens:get-proj-coords-dask-deprecated into ff45d3f on pytroll:master.