chore(mailmap): Use Frank's gmail address

Signed-off-by: Frank Viernau <frank.viernau@gmail.com>

Author: fviernau

.mailmap

@@ -7,10 +7,10 @@ Christian Decker <christian.decker@lookslikematrix.de> <chrisdecker1201@users.no
 Daniel Eder <daniel.eder@magenta.at> <1525711+daniel-eder@users.noreply.github.com>
 Dinesh Ravi <dineshr93@gmail.com>
 dependabot[bot] <dependabot[bot]@users.noreply.github.com> <49699333+dependabot[bot]@users.noreply.github.com>
-Frank Viernau <frank_viernau@epam.com> <42963794+fviernau@users.noreply.github.com>
-Frank Viernau <frank_viernau@epam.com> <frank.viernau@gmail.com>
-Frank Viernau <frank_viernau@epam.com> <frank.viernau@here.com>
-Frank Viernau <frank_viernau@epam.com> <x9fviern@zeiss.com>
+Frank Viernau <frank.viernau@gmail.com> <42963794+fviernau@users.noreply.github.com>
+Frank Viernau <frank.viernau@gmail.com> <frank_viernau@epam.com>
+Frank Viernau <frank.viernau@gmail.com> <frank.viernau@here.com>
+Frank Viernau <frank.viernau@gmail.com> <x9fviern@zeiss.com>
 François Barbe <f.barbe@lectra.com>
 François Barbe <f.barbe@lectra.com> <fb33@users.noreply.github.com>
 François Barbe <f.barbe@lectra.com> <fbarbe@yahoo.fr>