libidn11 not found

[flagarde]

Thx for this action !

In some ubuntu runner I had the error with libidn11 not found (cmake3.3 and cmake 3.5). A hacky fix is to do :

sudo apt-get update ; sudo apt-get install --no-install-recommends -y libidn12; sudo ln -s /usr/lib/x86_64-linux-gnu/libidn.so.12 /usr/lib/x86_64-linux-gnu/libidn.so.11

Maybe this could be done one this action directly