Rename package: Slic3rPE-1.42.0 to PrusaSlicer-2.0.0

[Gigahawk]

No description provided.

[Chocimier]

Auxiliary package could be better, see attica.

[Johnnynator]

musl builds fails

[ 94%] Building CXX object src/slic3r/CMakeFiles/libslic3r_gui.dir/Utils/Serial.cpp.o
/builddir/PrusaSlicer-version_2.0.0/src/slic3r/Utils/Serial.cpp:45:11: fatal error: sys/unistd.h: No such file or directory
  #include <sys/unistd.h>
           ^~~~~~~~~~~~~~

you can just change the include to unistd.h instead.

[Gigahawk]

@Johnnynator fixed.