treewide: simplify pkgs.stdenv.lib -> pkgs.lib

The library does not depend on stdenv, that `stdenv` exposes `lib` is
an artifact of the ancient origins of nixpkgs.

pkgs/development/interpreters/erlang/R16B02-basho.nix

@@ -59,7 +59,7 @@ mkDerivation {
     knownVulnerabilities = [ "CVE-2017-1000385" ];
 
     platforms = ["x86_64-linux" "x86_64-darwin"];
-    license = pkgs.stdenv.lib.licenses.asl20;
-    maintainers = with pkgs.stdenv.lib.maintainers; [ mdaiter ];
+    license = pkgs.lib.licenses.asl20;
+    maintainers = with pkgs.lib.maintainers; [ mdaiter ];
   };
 }