CI: upgrade pyinstaller for bootloader

Author: ptpt

script/build_bootloader.ps1

@@ -1,7 +1,7 @@
 # build bootloaders
 # to fix the virus false detection e.g. https://www.virustotal.com/gui/file/a2e8d8287f53e1691e44352b7fbc93038b36ad677d1faacfc1aa875de92af5a6
 python3 -m pip uninstall -y pyinstaller
-git clone --depth=1 --branch v5.12.0 https://github.com/pyinstaller/pyinstaller.git pyinstaller_git
+git clone --depth=1 --branch v6.15.0 https://github.com/pyinstaller/pyinstaller.git pyinstaller_git
 cd pyinstaller_git/bootloader # pwd: ./pyinstaller_git/bootloader
 python3 ./waf all
 git diff