bump upcoming version

CHANGELOG.md

@@ -1,12 +1,15 @@
 # Changelog
 MLEM uses [semantic versioning](https://semver.org/).
 
-The newest version in this changelog is the one that is currently in development. The changelog for unreleased versions might be edited over time as new features get added, changed or removed. To see the newest released version, check out the [release branch](https://github.com/Ellpeck/MLEM/tree/release).
+This changelog also contains information on versions that have yet to be released. The changelog for unreleased versions might be edited over time as new features get added, changed or removed. To see the newest released version's code, check out the [release branch](https://github.com/Ellpeck/MLEM/tree/release).
 
 Jump to version:
-- [5.0.0 (Unreleased)](#500-unreleased)
+- [5.1.0 (Unreleased)](#510-unreleased)
+- [5.0.0](#500)
 
-## 5.0.0 (Unreleased)
+## 5.1.0 (Unreleased)
+
+## 5.0.0
 ### MLEM
 Additions
 - Added some Collection extensions, namely for dealing with combinations

build.cake

@@ -2,7 +2,7 @@
 #tool docfx.console&version=2.51.0
 
 // this is the upcoming version, for prereleases
-var version = Argument("version", "5.0.0");
+var version = Argument("version", "5.1.0");
 var target = Argument("target", "Default");
 var branch = Argument("branch", "main");
 var config = Argument("configuration", "Release");