x264-unstable: drop

It has been updated in nixpkgs.

default.nix

@@ -48,6 +48,4 @@ in
   vgmstream = callPackage ./vgmstream { };
 
   VisiCut = callPackage ./VisiCut { };
-
-  x264-unstable = prev.x264.overrideAttrs (callPackage ./x264-unstable { });
 }

flake.nix

@@ -59,8 +59,7 @@
             snownews
             textidote
             unxwb
-            vgmstream
-            x264-unstable;
+            vgmstream;
 
           mpvScripts = lib.recurseIntoAttrs {
             inherit (pkgs.mpvScripts)

x264-unstable/default.nix

@@ -1,18 +0,0 @@
-{ lib, fetchFromGitLab }:
-
-o: o // rec {
-  version = "unstable-2021-04-19";
-
-  src = fetchFromGitLab {
-    domain = "code.videolan.org";
-    owner = "videolan";
-    repo = o.pname;
-    rev = "b684ebe04a6f80f8207a57940a1fa00e25274f81";
-    sha256 = "06r6m1v88m532wbhk6al9imrsn1inwdjzrpmp97wrbdg6b2naygd";
-  };
-
-  meta = with lib; o.meta // {
-    description = "${o.meta.description} (unstable version)";
-    maintainers = with maintainers; [ sbruder ];
-  };
-}