Prepare for 5.1.1

Author: benoit74

CHANGELOG.md

@@ -5,6 +5,8 @@ All notable changes to this project are documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html) (as of version 1.5.0).
 
+## [Unreleased]
+
 ## [5.1.0] - 2025-01-21
 
 ### Changed

src/zimscraperlib/__about__.py

@@ -1 +1 @@
-__version__ = "5.1.0"
+__version__ = "5.1.1-dev0"