Bump Bannerlord.ReferenceAssemblies from 1.1.6.26219 to 1.2.8.31530

Bumps [Bannerlord.ReferenceAssemblies](https://github.com/BUTR/Bannerlord.ReferenceAssemblies) from 1.1.6.26219 to 1.2.8.31530.
- [Commits](https://github.com/BUTR/Bannerlord.ReferenceAssemblies/commits)

---
updated-dependencies:
- dependency-name: Bannerlord.ReferenceAssemblies
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Directory.Build.props

@@ -1,7 +1,7 @@
 <Project>
   <PropertyGroup>
     <Version>3.0.3.0</Version>
-    <GameVersion>1.1.6.26219</GameVersion>
+    <GameVersion>1.2.8.31530</GameVersion>
     <GameBranch>Stable</GameBranch>
     <DepotName>public</DepotName>
     <HarmonyVersion>2.2.2</HarmonyVersion>