Merge remote-tracking branch 'upstream/master' into ufunc-vectorize-meta

* upstream/master:
  Add an example notebook using apply_ufunc to vectorize 1D functions (pydata#3629)
  Use encoding['dtype'] over data.dtype when possible within CFMaskCoder.encode (pydata#3652)
  allow passing any iterable to drop when dropping variables (pydata#3693)
  Typo on DataSet/DataArray.to_dict documentation (pydata#3692)
  Fix mypy type checking tests failure in ds.merge (pydata#3690)
  Explicitly convert result of pd.to_datetime to a timezone-naive type (pydata#3688)
  ds.merge(da) bugfix (pydata#3677)
  fix docstring for combine_first: returns a Dataset (pydata#3683)
  Add option to choose mfdataset attributes source. (pydata#3498)
  How do I add a new variable to dataset. (pydata#3679)
  Add map_blocks example to whats-new (pydata#3682)
  Make dask names change when chunking Variables by different amounts. (pydata#3584)
  raise an error when renaming dimensions to existing names (pydata#3645)
  Support swap_dims to dimension names that are not existing variables (pydata#3636)
  Add map_blocks example to docs. (pydata#3667)
  add multiindex level name checking to .rename() (pydata#3658)

ci/requirements/doc.yml

@@ -14,6 +14,7 @@ dependencies:
   - jupyter_client
   - nbsphinx
   - netcdf4
+  - numba
   - numpy
   - numpydoc
   - pandas<0.25  # Hack around https://github.com/pydata/xarray/issues/3369

doc/data-structures.rst

@@ -353,6 +353,8 @@ setting) variables and attributes:
 This is particularly useful in an exploratory context, because you can
 tab-complete these variable names with tools like IPython.
 
+.. _dictionary_like_methods:
+
 Dictionary like methods
 ~~~~~~~~~~~~~~~~~~~~~~~
 

doc/examples.rst

@@ -10,3 +10,10 @@ Examples
     examples/visualization_gallery
     examples/ROMS_ocean_model
     examples/ERA5-GRIB-example
+
+Using apply_ufunc
+------------------
+.. toctree::
+    :maxdepth: 2
+
+    examples/apply_ufunc_vectorize_1d