pcb-4.2.2 released

Written for pcb by Bert Timmerman on 2020-01-19

Dear Users,

This is a hot fix and bugfixes release (no pcb file format change).

This release is required as the User Manual doesn't build with
ghostscript versions newer than 9.27, as these newer versions require an
additional argument:

  --permit-file-read

for input files.

Kind regards,

The pcb development team.