Attempt to fix tests that run C#

Author: SomeRanDev

.github/workflows/test.yml

@@ -24,6 +24,13 @@ jobs:
           version: latest
           platform: x64
 
+      - name: Setup dotnet
+        uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: |
+            3.1.x
+            5.0.x
+
       - name: Install & Check Haxe
         run: haxe -version