nimPackages.jsonschema: use buildNimPackage

pkgs/development/nim-packages/jsonschema/default.nix

···
-{ fetchFromGitHub }:
+{ lib, buildNimPackage, fetchFromGitHub, astpatternmatching }:
+
+buildNimPackage rec {
+  pname = "jsonschema";
+  version = "unstable-2019-09-12";
 
-fetchFromGitHub {
-  owner = "PMunch";
-  repo = "jsonschema";
-  rev = "7b41c03e3e1a487d5a8f6b940ca8e764dc2cbabf";
-  sha256 = "1js64jqd854yjladxvnylij4rsz7212k31ks541pqrdzm6hpblbz";
+  src = fetchFromGitHub {
+    owner = "PMunch";
+    repo = "jsonschema";
+    rev = "7b41c03e3e1a487d5a8f6b940ca8e764dc2cbabf";
+    sha256 = "1js64jqd854yjladxvnylij4rsz7212k31ks541pqrdzm6hpblbz";
+  };
+
+  propagatedBuildInputs = [ astpatternmatching ];
+
+  meta = with lib; {
+    homepage = "https://github.com/PMunch/jsonschema";
+    description = "Schema validation of JSON for Nim";
+    license = licenses.mit;
+    maintainers = [ maintainers.marsam ];
+  };
 }