remove pb (unmaintained since 2020) (#3564)

- `WARNING:awesome_lint.py: pb: last updated -1040 days, 9:53:39.977329 ago, older than 365 days`
- ref. https://github.com/awesome-selfhosted/awesome-selfhosted/issues/3558

README.md

@@ -1486,7 +1486,6 @@ A [pastebin](https://en.wikipedia.org/wiki/Pastebin) is a type of online content
 - [Pastefy](https://pastefy.ga) - Beautiful, simple and easy to deploy Pastebin with optional Client-Encryption, Multitab-Pastes, an API, a highlighted Editor and more. ([Source Code](https://github.com/interaapps/pastefy), [Clients](https://github.com/topics/pastefy-addon)) `MIT` `Java`
 - [Pastila](https://pastila.nl/) - Minimalistic paste service. Single page, zero click experience. ([Source Code](https://github.com/ClickHouse/pastila)) `Apache-2.0` `SQL`
 - [pasty](https://github.com/lus/pasty) - Pasty is a fast and lightweight code pasting server. ([Demo](https://pasty.lus.pm/)) `MIT` `Go`
-- [pb](https://github.com/ptpb/pb) - Lightweight pastebin (and url shortener) built using flask. `GPL-3.0` `Python`
 - [PrivateBin](https://privatebin.info/) - PrivateBin is a minimalist, opensource online pastebin/discussion board where the server has zero knowledge of hosted data. ([Demo](https://privatebin.net/), [Source Code](https://github.com/PrivateBin/PrivateBin)) `Zlib` `PHP`
 - [prologic pastebin](https://git.mills.io/prologic/pastebin) - Simple pastebin service with convenient api and CLI. ([Demo](https://paste.mills.io)) `MIT` `Go`
 - [PurritoBin](https://github.com/PurritoBin/PurritoBin) - Ultra fast, minimalistic, encrypted command line paste-bin, where the server has no knowledge of the paste data. `ISC` `C++`