Issue a warning on PowerShell 6 end-of-life (#540) (#541)

* Add PowerShell6EndOfLifeWarning message

* Log the warning

* Move logging the message to PowerShellManager

* Add "Your Function app is still supported"

* Fix unit test

(cherry picked from commit 3f4a365)

Author: AnatoliB

src/PowerShell/PowerShellManager.cs

@@ -103,6 +103,8 @@ internal void Initialize()
         {
             if (!_runspaceInited)
             {
+                Logger.Log(isUserOnlyLog: true, LogLevel.Warning, PowerShellWorkerStrings.PowerShell6EndOfLifeWarning);
+
                 // Register stream events
                 RegisterStreamEvents();
                 // Deploy functions from the function App

src/resources/PowerShellWorkerStrings.resx

@@ -319,4 +319,7 @@
   <data name="SettingCurrentDirectory" xml:space="preserve">
     <value>Setting current directory to '{0}'.</value>
   </data>
+  <data name="PowerShell6EndOfLifeWarning" xml:space="preserve">
+    <value>The Function app uses PowerShell Core 6. Your Function app is still supported, but this version of PowerShell reached end of life, so it is strongly recommended that you migrate the Function app to PowerShell 7. For more details, see https://aka.ms/functions-powershell-6-to-7.</value>
+  </data>
 </root>

test/Unit/PowerShell/PowerShellManagerTests.cs

@@ -344,8 +344,7 @@ public void PSManagerCtorRunsProfileByDefault()
             s_testLogger.FullLog.Clear();
             NewTestPowerShellManager(s_testLogger);
 
-            Assert.Single(s_testLogger.FullLog);
-            Assert.Equal($"Trace: No 'profile.ps1' is found at the function app root folder: {FunctionLoader.FunctionAppRootPath}.", s_testLogger.FullLog[0]);
+            Assert.Contains($"Trace: No 'profile.ps1' is found at the function app root folder: {FunctionLoader.FunctionAppRootPath}.", s_testLogger.FullLog);
         }
 
         [Fact]