Update `.mailmap` (#7871)

Marshall Bowers created 

This PR updates the `.mailmap` file to merge some commit authors using
multiple emails.

Release Notes:

- N/A

Change summary

.mailmap | 2 ++
1 file changed, 2 insertions(+)

Detailed changes

.mailmap 🔗 

@@ -11,6 +11,8 @@
 
 Antonio Scandurra <me@as-cii.com>
 Antonio Scandurra <me@as-cii.com> <antonio@zed.dev>
+Christian Bergschneider <christian.bergschneider@gmx.de>
+Christian Bergschneider <christian.bergschneider@gmx.de> <magiclake@gmx.de>
 Conrad Irwin <conrad@zed.dev>
 Conrad Irwin <conrad@zed.dev> <conrad.irwin@gmail.com>
 Greg Morenz <greg-morenz@droid.cafe>