Added Service Point Manager call to force Tls12. (#6310)

Calls [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12 during bootstrap to download PowerShell core to avoid an error.

tools/install-powershell.ps1

@@ -91,6 +91,11 @@ $architecture = if (-not $IsWinEnv) {
 $tempDir = Join-Path ([System.IO.Path]::GetTempPath()) ([System.IO.Path]::GetRandomFileName())
 New-Item -ItemType Directory -Path $tempDir -Force > $null
 try {
+    # Setting Tls to 12 to prevent the Invoke-WebRequest : The request was
+    # aborted: Could not create SSL/TLS secure channel. error.
+    $originalValue = [Net.ServicePointManager]::SecurityProtocol
+    [Net.ServicePointManager]::SecurityProtocol = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12
+
     if ($Daily) {
         if (-not (Get-Module -Name PackageManagement -ListAvailable)) {
             throw "PackageManagement module is required to install daily PowerShell Core."
@@ -227,5 +232,8 @@ try {
         Write-Host "Please restart pwsh" -ForegroundColor Magenta
     }
 } finally {
+    # Restore original value
+    [Net.ServicePointManager]::SecurityProtocol = $originalValue
+
     Remove-Item -Path $tempDir -Recurse -Force -ErrorAction SilentlyContinue
 }