Release how-to

Here are the step by step instructions to release a new version of xESMF.

1. Make sure CHANGES.rst is up to date and includes a section on the version to be released, usually this is done through a pull request.

2. On GitHub, go the Releases page and click on Draft a new release;

3. Enter new version in Tag version (e.g. v<major>.<minor>.<patch>);

4. Enter the Release title (e.g. the same tag);

5. Copy the relevant section of CHANGES.rst in the description;

6. Click Publish release;