Update .Net SDK to 3.1.408 (#1630)

Author: bergmeister

.devcontainer/Dockerfile

@@ -1,6 +1,6 @@
 # Copyright (c) Microsoft Corporation. All rights reserved.
 # Licensed under the MIT License.
 
-FROM mcr.microsoft.com/dotnet/core/sdk:3.1.101
+FROM mcr.microsoft.com/dotnet/core/sdk:3.1.408
 
 RUN pwsh --command Install-Module platyPS,Pester -Force

global.json

@@ -1,5 +1,5 @@
 {
     "sdk": {
-        "version": "3.1.101"
+        "version": "3.1.408"
     }
 }

tools/releaseBuild/Image/DockerFile

@@ -18,8 +18,8 @@ RUN Import-Module PackageManagement; `
     Install-ChocolateyPackage -PackageName git -Executable git.exe; `
     Install-ChocolateyPackage -PackageName nuget.commandline -Executable nuget.exe -Cleanup; `
     Install-Module -Force -Name platyPS -Repository PSGallery; `
-    Invoke-WebRequest -Uri https://raw.githubusercontent.com/dotnet/cli/master/scripts/obtain/dotnet-install.ps1 -outfile C:/dotnet-install.ps1; `
-    C:/dotnet-install.ps1 -Channel Release -Version 2.1.4; `
+    Invoke-WebRequest -Uri https://dot.net/v1/dotnet-install.ps1 -OutFile C:/dotnet-install.ps1; `
+    C:/dotnet-install.ps1 -Version 3.1.408; `
     Add-Path C:/Users/ContainerAdministrator/AppData/Local/Microsoft/dotnet;
 
 COPY buildPSSA.ps1 containerFiles/buildPSSA.ps1