kdePackages.merkuro: add missing dependency on qtlocation

https://github.com/KDE/merkuro/commit/8a29fe2c16a8da123b52a9cc804c4a92b1c610f9

pkgs/kde/gear/merkuro/default.nix

···
 {
   mkKdeDerivation,
+  qtlocation,
   qtsvg,
   libplasma,
 }:
···
   pname = "merkuro";
 
   extraBuildInputs = [
+    qtlocation
     qtsvg
     libplasma
   ];