maintainers: rename geistesk to oxzi

For reasons I have renamed my GitHub account and would like to include
this name change here.

pkgs/tools/misc/umlet/default.nix

@@ -45,7 +45,7 @@ stdenv.mkDerivation rec {
     '';
     homepage = "http://www.umlet.com";
     license = licenses.gpl3;
-    maintainers = with maintainers; [ geistesk ];
+    maintainers = with maintainers; [ oxzi ];
     platforms = platforms.all;
   };
 }

pkgs/tools/networking/go-shadowsocks2/default.nix

@@ -19,6 +19,6 @@ buildGoPackage rec {
     description = "Fresh implementation of Shadowsocks in Go";
     homepage = "https://github.com/shadowsocks/go-shadowsocks2/";
     license = licenses.asl20;
-    maintainers = with maintainers; [ geistesk ];
+    maintainers = with maintainers; [ oxzi ];
   };
 }

pkgs/tools/security/hash_extender/default.nix

@@ -25,6 +25,6 @@ stdenv.mkDerivation {
     description = "Tool to automate hash length extension attacks";
     homepage = "https://github.com/iagox86/hash_extender";
     license = licenses.bsd3;
-    maintainers = with maintainers; [ geistesk ];
+    maintainers = with maintainers; [ oxzi ];
   };
 }

pkgs/tools/text/smu/default.nix

@@ -22,7 +22,7 @@ stdenv.mkDerivation rec {
     description = "simple markup - markdown like syntax";
     homepage = "https://github.com/Gottox/smu";
     license = licenses.mit;
-    maintainers = with maintainers; [ geistesk ];
+    maintainers = with maintainers; [ oxzi ];
   };
 }