[sqwebmail] New releases of Courier packages

[Sam V. <mr...@co...>]

Download: https://www.courier-mta.org/download.html

New releases of all Courier packages.

Changes:

• Use libidn2 instead of libidn.

• "make install" creates relative, instead of absolute, symbolic links.

• debuild script: update lintian overrides, add pkg-config to build  
dependencies.