0.6.0rc2

Release Notes
-------------
Minor relase in preparation of a new CalVer versioning
following the lead of *fMRIPrep*.
This release contains a fair amount of maintenance work to
ensure synchronizity with the TemplateFlow archive
(https://github.com/templateflow/templateflow).
These maintenance actions drive the development towards
establishing a peer-reviewed, lightweight template submission
protocol.
With thanks to V. Fonov for contributing the new
``tpl-MNI152NLin2009cSym``.

CHANGES
-------
  * ENH: Update the internal index of *TemplateFlow* (#40)
  * ENH: Automatic generation of template citations (#35)
  * MAINT: Set-up a GitHub action to test installation
    alternatives (see #23).
  * MAINT: Migrate to ``setuptools_scm`` (#42)
  * MAINT: Run black on the whole tree (#41)
  * MAINT: Transfer the burden of keeping skeleton updated
    over to the archive (#39)