mullvad-browser: 12.0.7 -> 12.5

(cherry picked from commit 06707cf89660ce60e45344d353c552fff1a0e709)

pkgs/applications/networking/browsers/mullvad-browser/default.nix

···
       ++ lib.optionals mediaSupport [ ffmpeg ]
   );
 
-  version = "12.0.7";
+  version = "12.5";
 
   sources = {
     x86_64-linux = fetchurl {
       url = "https://cdn.mullvad.net/browser/${version}/mullvad-browser-linux64-${version}_ALL.tar.xz";
-      hash = "sha256-8TcC39A9VFyhFb+pfefzvwJqXq1yF7C2YDcbCyEa0yo=";
+      hash = "sha256-RTDFi+vMkzRtDFgv9sP1bfIeWzzXR307aoMhNiT6vRs=";
     };
   };