Update autoinstall script

Switch from FairSoft version jun19p2 to jun19p3. In the FairSoft release jun19p2 some download URLs have changed such that the installation did not work any longer.

added BugFix Build System labels

Dear @f.uhlig, @v.friese, @p.-a.loizeau,

you have been identified as code owner of at least one file which was changed with this merge request.

Please check the changes and approve them or request changes.

added CodeOwners label

Should we maybe set the Dev version to nov20p1 or apr21p1? So that adventurous people start trying them in advance?

I would also move the Fairroot Dev version to v18.4.5 to get the patch for the Task based monitors.

This we can do in second step. Currently there are issues with AnalysisTree when using nov20 or apr21. After this are sorted out I would like to move to apr21 anyway.

@f.uhlig

This change allowed installation of FairSoft to go through without issue. See https://lxcbmredmine01.gsi.de/issues/2159

@p.-a.loizeau

Does anyone actually use this dev option? If so, I would recommend we make this change in one commit.

merged