KOMA-Script doesn't require parskip package.

[ascherer]

Instead, scrlttr2 issues the following warning:

Class scrlttr2 Warning: Usage of package `parskip' together
(scrlttr2)              with a KOMA-Script class is not recommended.
(scrlttr2)              I'd suggest to use option
(scrlttr2)              `parskip' with one of it's several values.
(scrlttr2)              Nevertheless, using requested
(scrlttr2)              package `parskip' on input line 16.

[ascherer]

In Verbindung mit PR #8 kann man natürlich auch letteroption: parskip=half direkt in example/letter.md einfügen.