* upstream/master:
  minor lint tweaks (pydata#3429)
  Hack around pydata#3440 (pydata#3442)
  Update Terminology page to account for multidimensional coordinates (pydata#3410)
  Use cftime master for upstream-dev build (pydata#3439)

* upstream/master: (27 commits)
  drop_vars; deprecate drop for variables (pydata#3475)
  uamiv test using only raw uamiv variables (pydata#3485)
  Optimize dask array equality checks. (pydata#3453)
  Propagate indexes in DataArray binary operations. (pydata#3481)
  python 3.8 tests (pydata#3477)
  __dask_tokenize__ (pydata#3446)
  Type check sentinel values (pydata#3472)
  Fix typo in docstring (pydata#3474)
  fix test suite warnings re `drop` (pydata#3460)
  Fix integrate docs (pydata#3469)
  Fix leap year condition in monthly means example (pydata#3464)
  Hypothesis tests for roundtrip to & from pandas (pydata#3285)
  unpin cftime (pydata#3463)
  Cleanup whatsnew (pydata#3462)
  enable xr.ALL_DIMS in xr.dot (pydata#3424)
  Merge stable into master (pydata#3457)
  upgrade black verison to 19.10b0 (pydata#3456)
  Remove outdated code related to compatibility with netcdftime (pydata#3450)
  Remove deprecated behavior from dataset.drop docstring (pydata#3451)
  jupyterlab dark theme (pydata#3443)
  ...

* origin/fix/allow_lazy:

Co-Authored-By: Mathias Hauser <mathause@users.noreply.github.com>

Co-Authored-By: Mathias Hauser <mathause@users.noreply.github.com>

* upstream/master:
  add missing pint integration tests (pydata#3508)
  DOC: update bottleneck repo url (pydata#3507)
  add drop_sel, drop_vars, map to api.rst (pydata#3506)
  remove syntax warning (pydata#3505)
  Dataset.map, GroupBy.map, Resample.map (pydata#3459)
  tests for datasets with units (pydata#3447)
  fix pandas-dev tests (pydata#3491)
  unpin pseudonetcdf (pydata#3496)
  whatsnew corrections (pydata#3494)