Use more portable #! for ps1

azure-pipelines/artifacts/_all.ps1

@@ -1,4 +1,4 @@
-#!/usr/bin/pwsh
+#!/usr/bin/env pwsh
 
 # This script returns all the artifacts that should be collected after a build.
 #

azure-pipelines/variables/_all.ps1

@@ -1,4 +1,4 @@
-#!/usr/bin/pwsh
+#!/usr/bin/env pwsh
 
 # This script returns a hashtable of build variables that should be set
 # at the start of a build or release definition's execution.

init.ps1

@@ -1,4 +1,4 @@
-#!/usr/bin/pwsh
+#!/usr/bin/env pwsh
 
 <#
 .SYNOPSIS

tools/Install-DotNetSdk.ps1

@@ -1,4 +1,4 @@
-#!/usr/bin/pwsh
+#!/usr/bin/env pwsh
 
 <#
 .SYNOPSIS

tools/Install-NuGetCredProvider.ps1

@@ -1,4 +1,4 @@
-#!/usr/bin/pwsh
+#!/usr/bin/env pwsh
 
 <#
 .SYNOPSIS