diffpdf from home:dliw project

需要 openSUSE Tumbleweed ，用 root 執行：

zypper addrepo https://download.opensuse.org/repositories/home:dliw/openSUSE_Tumbleweed/home:dliw.repo
zypper refresh
zypper install diffpdf

需要 15.6 ，用 root 執行：

zypper addrepo https://download.opensuse.org/repositories/home:dliw/15.6/home:dliw.repo
zypper refresh
zypper install diffpdf

需要 15.5 ，用 root 執行：

zypper addrepo https://download.opensuse.org/repositories/home:dliw/15.5/home:dliw.repo
zypper refresh
zypper install diffpdf