csound is marked for autoremoval from testing

[Debian testing autoremoval watch]

csound 1:6.13.0~dfsg-3 is marked for autoremoval from testing on 2020-04-02

It (build-)depends on packages with these RC bugs:
948018: getfem++: getfem++: b-d on python3-all-dev, but not built for all 
supported Python3 versions