WIP: Fix release dask version

[jbusecke]

In response to this PR, I am trying to phase out the dask < 2 requirement from the ci envs.

[codecov]

Codecov Report

Merging #45 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #45   +/-   ##
=======================================
  Coverage   46.49%   46.49%           
=======================================
  Files          13       13           
  Lines        1314     1314           
  Branches      296      296           
=======================================
  Hits          611      611           
  Misses        654      654           
  Partials       49       49

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 02d2e32...aa45f74. Read the comment docs.

[jbusecke]

I expect these tests to fail, since the fix has not been released upstream. Just noting this here so I can rebuild and merge as soon as the version is released.

[jbusecke]

Somehow conda resolves xarray in the py37 environment to 0.14.1 instead of 0.15.0. It seems like the conda version has not been bumped yet. Ill wait a bit more for this.