libwebsockets: 2.4.2 -> 3.0.0

Semi-automatic update generated by https://github.com/ryantm/nixpkgs-update tools.

This update was made based on information from https://repology.org/metapackage/libwebsockets/versions.

These checks were done:

- built on NixOS
- Warning: no binary found that responded to help or version flags. (This warning appears even if the package isn't expected to have binaries.)
- found 3.0.0 with grep in /nix/store/m8jcyxq9zxn19vzwmvy8jld4kmjcwnmj-libwebsockets-3.0.0
- directory tree listing: https://gist.github.com/3fda3b4331b75bec575d1a71ba21e84a

pkgs/development/libraries/libwebsockets/default.nix

@@ -2,13 +2,13 @@
 
 stdenv.mkDerivation rec {
   name = "libwebsockets-${version}";
-  version = "2.4.2";
+  version = "3.0.0";
 
   src = fetchFromGitHub {
     owner = "warmcat";
     repo = "libwebsockets";
     rev = "v${version}";
-    sha256 = "0gbprzsi054f9gr31ihcf0cq7zfkybrmdp6894pmzb5hcv4wnh9i";
+    sha256 = "0cz4f05qd9b2bm27h5pkwym2cl7ff73lgirzwjppwf9b18if58yv";
   };
 
   buildInputs = [ cmake openssl zlib libuv ];