Upgrade to version 3.5.0

Should be enough for getdp to go green in https://release.debian.org/transitions/html/auto-petsc.html

I am no getdp user, but I did try the demo reported in https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=927140 and can confirm that the bug report can be closed. I haven't mentioned 927140 explicitly because the fix probably had already happened in previous releases.

EDIT: The fix did indeed happen in the latest commit on master.