bump stage0 go version to go1.20.6

(cherry picked from commit 3242a72)

update stage0 checksums

(cherry picked from commit 694f922)

eng/utilities.ps1

@@ -24,29 +24,29 @@ function Get-Stage0GoRoot() {
   # pre-installed. This CI script installs a consistent, official version of Go to a directory in
   # $HOME to handle this. This also makes it easier to locally repro issues in CI that involve a
   # specific version of Go. The downloaded copy of Go is called the "stage 0" version.
-  $stage0_go_version = '1.18.7'
+  $stage0_go_version = '1.20.6'
 
   $proc_arch = ([System.Runtime.InteropServices.RuntimeInformation]::ProcessArchitecture).ToString().ToLowerInvariant()
   if ($IsWindows) {
     switch ($proc_arch) {
       'x64' {
-        $stage0_go_sha256 = '8c23c6ae7777df883ccc2fd07a90c3ac7fab3eb7398c0e2f39c7cb27ee06517e'
+        $stage0_go_sha256 = 'b67dd7f2b4589701e53c98e348e1b4d9a7c3536dc316941172b2f0b60ae4ce5f'
         $stage0_go_suffix = 'windows-amd64.zip'
       }
       'arm64' {
-        $stage0_go_sha256 = '14a1f33da77bcecea3c1f9ad5ca2363e0835fb77e83b3b1e09b922fd91fb66e1'
+        $stage0_go_sha256 = '9027e52be386e779ef1a0c938994ee2361689496ac832100407238f5ed0fd82a'
         $stage0_go_suffix = 'windows-arm64.zip'
       }
       Default { throw "Unable to match Windows '$proc_arch' to an architecture supported by the Microsoft scripts to build Go." }
     }
   } elseif ($IsLinux) {
     switch ($proc_arch) {
       'x64' {
-        $stage0_go_sha256 = '6c967efc22152ce3124fc35cdf50fc686870120c5fd2107234d05d450a6105d8'
+        $stage0_go_sha256 = 'b945ae2bb5db01a0fb4786afde64e6fbab50b67f6fa0eb6cfa4924f16a7ff1eb'
         $stage0_go_suffix = 'linux-amd64.tar.gz'
       }
       'arm64' {
-        $stage0_go_sha256 = 'dceea023a9f87dc7c3bf638874e34ff1b42b76e3f1e489510a0c5ffde0cad438'
+        $stage0_go_sha256 = '4e15ab37556e979181a1a1cc60f6d796932223a0f5351d7c83768b356f84429b'
         $stage0_go_suffix = 'linux-arm64.tar.gz'
       }
       Default { throw "Unable to match Linux '$proc_arch' to an architecture supported by the Microsoft scripts to build Go." }