allow upgrade-uuid to be customized in build script

dist/win/build.bat

@@ -1,12 +1,16 @@
 @echo off
+:: Default values for Cryptomator builds
 SET APPNAME="Cryptomator"
+SET UPGRADE_UUID="bda45523-42b1-4cae-9354-a45475ed4775"
 SET VENDOR="Skymatic GmbH"
 SET FIRST_COPYRIGHT_YEAR=2016
 SET ABOUT_URL="https://cryptomator.org"
 SET UPDATE_URL="https://cryptomator.org/downloads/"
 SET HELP_URL="https://cryptomator.org/contact/"
+
 powershell -NoLogo -NoExit -ExecutionPolicy Unrestricted -Command .\build.ps1^
  -AppName %APPNAME%^
+ -UpgradeUUID "%UPGRADE_UUID%"^
  -Vendor ""%VENDOR%""^
  -CopyrightStartYear %FIRST_COPYRIGHT_YEAR%^
  -AboutUrl "%ABOUT_URL%"^

dist/win/build.ps1

@@ -1,5 +1,6 @@
 Param(
 	[Parameter(Mandatory, HelpMessage="Please provide a name for the app")][string] $AppName,
+	[Parameter(Mandatory, HelpMessage="Please provide the windows upgrade uuid for the app")][string] $UpgradeUUID,
 	[Parameter(Mandatory, HelpMessage="Please provide the name of the vendor")][string] $Vendor,
 	[Parameter(Mandatory, HelpMessage="Please provide the starting year for the copyright notice")][int] $CopyrightStartYear,
 	[Parameter(Mandatory, HelpMessage="Please provide a help url")][string] $HelpUrl,
@@ -107,7 +108,7 @@ $Env:JP_WIXWIZARD_RESOURCES = "$buildDir\resources"
 & "$Env:JAVA_HOME\bin\jpackage" `
 	--verbose `
 	--type msi `
-	--win-upgrade-uuid bda45523-42b1-4cae-9354-a45475ed4775 `
+	--win-upgrade-uuid  $UpgradeUUID `
 	--app-image $AppName `
 	--dest installer `
 	--name $AppName `