tockloader: remove myself from maintainers

Sadly the only device I had that was requiring this was an nRF52840 MDK
USB dongle and I apparently broke its bootloader, so it won't get
recognized anymore.

pkgs/development/tools/misc/tockloader/default.nix

@@ -31,7 +31,7 @@ python3Packages.buildPythonApplication rec {
     homepage = "https://github.com/tock/tockloader";
     license = licenses.mit;
     description = "Tool for programming Tock onto hardware boards";
-    maintainers = with maintainers; [ hexa ];
+    maintainers = with maintainers; [ ];
   };
 }