add test for powershell:7.1.4 and powershell:7.2.0-preview.10

Build/build-tasks.ps1

@@ -170,6 +170,7 @@ task PsDesktopTest {
 }
 
 task PsCoreTest {
+    # show-powershell-images.ps1
     $images = $(
         "mcr.microsoft.com/powershell:6.1.0-ubuntu-18.04"
         , "mcr.microsoft.com/powershell:6.1.1-alpine-3.8"
@@ -188,7 +189,8 @@ task PsCoreTest {
         , "mcr.microsoft.com/powershell:7.1.1-ubuntu-20.04"
         , "mcr.microsoft.com/powershell:7.1.2-ubuntu-20.04"
         , "mcr.microsoft.com/powershell:7.1.3-ubuntu-20.04"
-        , "mcr.microsoft.com/powershell:7.2.0-preview.7-ubuntu-20.04")
+        , "mcr.microsoft.com/powershell:7.1.4-ubuntu-20.04"
+        , "mcr.microsoft.com/powershell:7.2.0-preview.10-ubuntu-20.04")
 
     $builds = @()
     foreach ($image in $images) {

Build/show-powershell-images.ps1

@@ -0,0 +1,31 @@
+$ErrorActionPreference = "Stop"
+
+function Get-ShortVersion {
+    [CmdletBinding()]
+    param (
+        [Parameter(ValueFromPipeline)]
+        [string]
+        $FullVersion
+    )
+
+    process {
+        $parts = $FullVersion -split "-"
+        $result = $parts[0]
+
+        if ($parts[1] -like "preview*") {
+            $result += "-" + $parts[1]
+        }
+
+        return $result
+    }
+}
+
+(Invoke-RestMethod -Uri "https://mcr.microsoft.com/v2/powershell/tags/list").tags `
+    | Where-Object {$_ -Like "[0-9]*"} `
+    | Get-ShortVersion `
+    | Sort-Object -Unique
+
+# (Invoke-RestMethod -Uri "https://mcr.microsoft.com/v2/powershell/tags/list").tags `
+#     | Where-Object {$_ -Like "7.2.0*"} `
+#     | Where-Object {($_ -Like "*ubuntu*") -or ($_ -Like "*alpine*")} `
+#     | Sort-Object