Update .mailmap file

Create by command

```
git log --raw | grep "^Author: " | sort | uniq | cut -d ' ' -f2- | sed 's/^//' > .mailmap
```

.mailmap

@@ -34,6 +34,8 @@ Daniel Hedberg <dhedberg@wolfram.com>
 Dietmar Winkler <dietmar.winkler@dwe.no>
 Dietmar Winkler <dietmar.winkler@usn.no>
 Dietmar Winkler <dietmarw@7ce873d0-865f-4ce7-a662-4bb36ea78beb>
+Dirk Zimmer <dirk.zimmer@dlr.de>
+Dirk Zimmer <dr.dirk.zimmer@gmail.com>
 Elena Shmoylova <eshmoylova@users.noreply.github.com>
 Francesco Casella <Francesco@7ce873d0-865f-4ce7-a662-4bb36ea78beb>
 Francesco Casella <fcasella@7ce873d0-865f-4ce7-a662-4bb36ea78beb>
@@ -101,9 +103,9 @@ Peter Harman <peter.harman@deltatheta.com>
 Peter Harman <pharman@7ce873d0-865f-4ce7-a662-4bb36ea78beb>
 Philip Jordan <pjordan@7ce873d0-865f-4ce7-a662-4bb36ea78beb>
 Quentin Lambert <quentinl@wolfram.com>
-Rüdiger Franke <ruediger.franke@de.abb.com>
 Rüdiger Franke <rdgfranke@gmail.com>
 Rüdiger Franke <rfranke@7ce873d0-865f-4ce7-a662-4bb36ea78beb>
+Rüdiger Franke <ruediger.franke@de.abb.com>
 Stefan Vorkoetter <svorkoetter@maplesoft.com>
 Stefan Wischhusen <wischhusen@7ce873d0-865f-4ce7-a662-4bb36ea78beb>
 Stefan Wischhusen <wischhusen@xrg-simulation.de>