Update my username (#4846)

I use both but it's clearer for everybody if I just stick to one for cncf things

Signed-off-by: Friedrich Gonzalez <friedrichg@gmail.com>

Signed-off-by: Friedrich Gonzalez <friedrichg@gmail.com>

Author: friedrichg

MAINTAINERS

@@ -1,7 +1,7 @@
 Alan Protasio, Amazon Web Services <alanprot@gmail.com> (@alanprot)
 Alvin Lin, Amazon Web Services <alvinlin123@gmail.com> (@alvinlin123)
 Bryan Boreham, Grafana Labs <bjboreham@gmail.com> (@bboreham)
-Friedrich Gonzalez, Adobe <friedrichg@gmail.com> (@friedrich-at-adobe)
+Friedrich Gonzalez, Adobe <friedrichg@gmail.com> (@friedrichg)
 Goutham Veeramachaneni, Grafana Labs <gouthamve@gmail.com> (@gouthamve)
 Jacob Lisi, Google <jacob.t.lisi@gmail.com> (@jtlisi)
 Tom Wilkie, Grafana Labs <tom.wilkie@gmail.com> (@tomwilkie)