Change PowerShell exe path in tasks.json

For some reason the new task runner was not executing PowerShell
correctly using the path that we specifed in tasks.json.  I've
simplified the path string to make this more reliable.

Author: daviwil

.vscode/tasks.json

@@ -2,7 +2,7 @@
     "version": "2.0.0",
 
     "windows": {
-        "command": "${env.windir}\\sysnative\\windowspowershell\\v1.0\\PowerShell.exe",
+        "command": "powershell.exe",
         "args": [ "-NoProfile", "-ExecutionPolicy", "Bypass" ]
     },
     "linux": {