0.4.0

Enhancements

• A new configuration setting append_step can be used to validate
  the step sizes between the labels of a coordinate variable associated with
  the append dimension. Its value can be a number for numerical labels
  or a time delta value of the form 8h (8 hours) or 2D (two days) for
  date/time labels. The value can also be negative. [#21]

• The configuration setting append_step can take the special values
  "+" and "-" which are used to verify that the labels are monotonically
  increasing and decreasing, respectively. [#20]

• It is now possible to reference environment variables
  in configuration files using the syntax ${ENV_VAR}. [#36]

• Added a demo Notebook exmaples/zappend-demo.ipynb and linked
  it by a binder badge in README.md. [#47]

Fixes

• When slice_source was given as class or function and passed
  to the zappend() function either as configuration entry or as keyword
  argument, a ValidationError was accidentally raised. [#49]

• Fixed an issue where an absolute lock file path was computed if the target
  Zarr path was relative in the local filesystem, and had no parent directory.
  [#45]

Full Changelog: v0.3.0...v0.4.0