Improve WriteString perf with SIMD
diff --git a/csharp/install_dotnet_sdk.ps1 b/csharp/install_dotnet_sdk.ps1
index 8bc967c..c78655c 100755
--- a/csharp/install_dotnet_sdk.ps1
+++ b/csharp/install_dotnet_sdk.ps1
@@ -17,4 +17,4 @@
 # The SDK versions to install should be kept in sync with versions
 # installed by kokoro/linux/dockerfile/test/csharp/Dockerfile
 &$InstallScriptPath -Version 2.1.802
-&$InstallScriptPath -Version 3.1.301
+&$InstallScriptPath -Version 5.0.102