sdk-artifact(build-installers): include the update-via-pacman.ps1 s…

…cript

This script is already used by the `sync` jobs that keep the Git for
Windows SDKs up to date.

We're about to use the same script in the automation that builds Git for
Windows' packages, so let's make sure that this script is available in
those scenarios.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

please.sh

@@ -3239,6 +3239,7 @@ create_sdk_artifact () { # [--out=<directory>] [--git-sdk=<directory>] [--archit
 		/usr/ssl/certs/ca-bundle.crt
 		/usr/share/pacman/
 		/var/lib/pacman/local/
+		/update-via-pacman.ps1
 
 		# Some other utilities required by `make-file-list.sh`
 		/usr/bin/cat.exe