v5.6.1

Release 5.6.1 (#2)

* all changes of a_util 5.6.1 merged in 5.6.0

* hint for Cmake added

* CMake hint improved

Co-authored-by: Ralf Belke <Ralf.Belke@audi.de>

First official public version

Adds / enhances actions

* puts everything into matrix which defines required platform dependend variables
* Upload artifacts with gh actions
* adds build_tags.yml which also uploads artifacts to release if tag is built
* adds artifact creation to build.yml and skips build for tags
* adds installations of required packages
* Adds branch and tag name detection