Convert to Cranko versioning

Still need to automate dealing with docs/conf.py, but mostly there.

.config/cranko/bootstrap.toml

@@ -0,0 +1,6 @@
+[[project]]
+qnames = [
+    'wwt_data_formats',
+    'pypa',
+]
+version = '0.4.1'

.config/cranko/config.toml

@@ -0,0 +1,5 @@
+[repo]
+upstream_urls = [
+  'git@github.com:WorldWideTelescope/wwt_data_formats.git',
+  'https://github.com/WorldWideTelescope/wwt_data_formats.git',
+]

setup.py

@@ -33,8 +33,8 @@ project homepage].
 
 
 setup_args = dict(
-    name = 'wwt_data_formats',
+    name = 'wwt_data_formats',  # cranko project-name
-    version = '0.5.0.dev0',  # also update docs/conf.py
+    version = '0.dev0',  # cranko project-version
     description = 'Low-level interface to AAS WorldWide Telescope data formats',
     long_description = get_long_desc(),
     long_description_content_type = 'text/markdown',