Squashed 'libs/protobuf/' content from commit fcd3b9a85

git-subtree-dir: libs/protobuf
git-subtree-split: fcd3b9a85ef36e46643dc30176cea1a7ad62e02b

csharp/install_dotnet_sdk.ps1

@@ -0,0 +1,20 @@
+#!/usr/bin/env powershell
+# Install dotnet SDK using the official dotnet-install.ps1 script
+
+Set-StrictMode -Version 2
+$ErrorActionPreference = 'Stop'
+
+# avoid "Unknown error on a send" in Invoke-WebRequest
+[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
+
+$InstallScriptUrl = 'https://dot.net/v1/dotnet-install.ps1'
+$InstallScriptPath = Join-Path  "$env:TEMP" 'dotnet-install.ps1'
+
+# Download install script
+Write-Host "Downloading install script: $InstallScriptUrl => $InstallScriptPath"
+Invoke-WebRequest -Uri $InstallScriptUrl -OutFile $InstallScriptPath
+
+# The SDK versions to install should be kept in sync with versions
+# installed by kokoro/linux/dockerfile/test/csharp/Dockerfile
+&$InstallScriptPath -Version 3.1.415
+&$InstallScriptPath -Version 6.0.100