Fixed: Gradle Wrapper is not downloaded with 18.12.03 (OFBIZ-12471)

I guess for a reason David misses the path to WindowsPowerShell as an
environment variable.

Follows advice here:
https://stackoverflow.com/questions/29778121/powershell-is-not-recognized-as-an-internal-or-external-command-operable-progr

Thanks: David S Hunter for report
diff --git a/init-gradle-wrapper.bat b/init-gradle-wrapper.bat
index 3440521..188c13a 100755
--- a/init-gradle-wrapper.bat
+++ b/init-gradle-wrapper.bat
@@ -23,4 +23,4 @@
     exit /b
 )
 
-pwsh  -command "  Start-Process pwsh -Verb RunAs \""-Command `\""cd '%cd%'; & 'gradle\init-gradle-wrapper.ps1';`\""\""   "
+%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\powershell.exe -command "  Start-Process pwsh -Verb RunAs \""-Command `\""cd '%cd%'; & 'gradle\init-gradle-wrapper.ps1';`\""\""   "