Remove PukiWiki (source code unreachable) (#4013)

- ref. https://github.com/awesome-selfhosted/awesome-selfhosted/issues/3558
- `https://ja.osdn.net/projects/pukiwiki/scm/git/pukiwiki/ : HTTPSConnectionPool(host='ja.osdn.net', port=443): Read timed out. (read timeout=10)`

README.md

@@ -2101,7 +2101,6 @@ _See also: [Wikimatrix](https://www.wikimatrix.org/), [Wiki Engines - WikiIndex]
 - [Pepperminty Wiki](https://github.com/sbrl/Pepperminty-Wiki) - Complete markdown-powered wiki contained in a single PHP file. ([Demo](https://starbeamrainbowlabs.com/labs/peppermint/build/)) `MPL-2.0` `PHP`
 - [PineDocs](https://github.com/xy2z/PineDocs) - Simple, fast, customizable and lightweight site for browsing files. `GPL-3.0` `PHP`
 - [PmWiki](https://www.pmwiki.org) - Wiki-based system for collaborative creation and maintenance of websites. `GPL-3.0` `PHP`
-- [PukiWiki](https://pukiwiki.osdn.jp/) - PukiWiki is a free, simple, open-source wiki management system. Minimalistic and simple design with many tools for collaborative work. Created in Japanese, so translator needed. ([Source Code](https://ja.osdn.net/projects/pukiwiki/scm/git/pukiwiki/)) `GPL-2.0` `PHP`
 - [Raneto](https://raneto.com/) - Raneto is an open source Knowledgebase platform that uses static Markdown files to power your Knowledgebase. ([Source Code](https://github.com/ryanlelek/Raneto)) `MIT` `Nodejs`
 - [TiddlyWiki](https://tiddlywiki.com/) - Reusable non-linear personal web notebook. ([Source Code](https://github.com/Jermolene/TiddlyWiki5)) `BSD-3-Clause` `Nodejs`
 - [Tiki](https://tiki.org/HomePage) - Wiki CMS Groupware with the most built-in features. ([Demo](https://tiki.org/Try-Tiki), [Source Code](https://sourceforge.net/p/tikiwiki/code/HEAD/tree/)) `LGPL-2.1` `PHP`