This project isn't needed anymore after the Qt v5.15 was dropped.
Regenerating hashes is needed after any archive upgrade. Change directory to the repository root and invoke:
.\tools\Get-DownloadsHash.ps1 -Platform Linux,Windows
The script knows which files to hash by the file extension, *.7z for Windows and *.bz2 and *.xz for Linux.
To upgrade ccache simply download the .tar.xz archive from https://github.com/ccache/ccache/releases
Upgrading clazy standalone isn't that simple, I'm using clazy standalone from QtCreator so it must by manually bzip-ed to clazy-standalone.tar.bz2 file using the following command:
tar cjvf ../clazy-standalone.tar.bz2 .