Set version to 8.1.0-rc.1

Directory.Build.props

@@ -1,7 +1,7 @@
 <Project>
   <!-- Auto-imported by every project in the repo; referenced via $(RaylibCsVersion). -->
   <PropertyGroup>
-    <RaylibCsVersion>8.1.0</RaylibCsVersion>
+    <RaylibCsVersion>8.1.0-rc.1</RaylibCsVersion>
   </PropertyGroup>
 
   <!-- The net8-era wasm workload treats any browser-wasm project as a wasm *app* and hooks

README.md

@@ -13,7 +13,7 @@ C# bindings for raylib, a simple and easy-to-use library to learn video games pr
 Raylib-cs targets net8.0, net10.0 and uses the [official 6.0 release](https://github.com/raysan5/raylib/releases/tag/6.0)
 to build the native libraries.
 
-### Version 8.1.0 of Raylib-cs supports the following runtimes:
+### Version 8.1.0-rc.1 of Raylib-cs supports the following runtimes:
 
 - **browser-wasm** *(raylib-6.0_webassembly)* 🆕
 - **linux-x64** *(raylib-6.0_linux_amd64)*