Modify CI workflow for Release build and artifact upload

Updated build command to use Release configuration and added step to upload build files.

Author: TimeAndTimeStudio

.github/workflows/dotnet.yml

@@ -29,4 +29,9 @@ jobs:
     - name: Restore
       run: dotnet tool restore
     - name: Build
-      run: dotnet build
+      run: dotnet build -c Release
+    - name: Upload Build Files
+      uses: actions/upload-artifact@v4
+      with:
+        name: BattleMushroom-Build
+        path: bin/