update to dev version (#11)

Author: OriolAbril

docs/source/contributing/how_to.md

@@ -3,7 +3,8 @@
 ## Making a new release
 
 1. Create a new branch
-1. Review the change log (`docs/source/changelog.md`)
+1. Review the change log (`docs/source/changelog.md`). The unreleased section
+   should be updated to the current version and release date _and not yet added_
 1. Update the version number in `__init__.py`. That is, remove the `dev` flag, it should not
    be increased.
 1. Rerun the notebooks in `docs/source/tutorials`
@@ -15,4 +16,5 @@
    go to [readthedocs](https://readthedocs.org/projects/xarray-einstats/) and
    add it.
 1. Bump the minor version, set the patch version to 0 and add the `dev` flag.
-   It should look like `0.2.0.dev0`
+   It should look like `0.2.0.dev0`. Also add the Unreleased section in
+   the changelog again.

src/xarray_einstats/__init__.py

@@ -10,4 +10,4 @@
 
 __all__ = ["einsum", "raw_einsum", "einsum_path", "matmul"]
 
-__version__ = "0.2.0"
+__version__ = "0.3.0.dev0"