fix: [#400] Fix mkdocs theme entrypoint for zettelkasten

Fixes #400

Author: timo-reymann

projects.yaml

@@ -175,7 +175,7 @@ projects:
   labels: [theme]
   category: theming
 - name: Zettelkasten
-  mkdocs_theme: zettelkasten-solarized-light
+  mkdocs_theme: zettelkasten
   mkdocs_plugin: [zettelkasten]
   github_id: buvis/mkdocs-zettelkasten
   pypi_id: mkdocs-zettelkasten