metar: switch to fetchFromGitHub, use unstable version format

pkgs/applications/misc/metar/default.nix

@@ -1,11 +1,12 @@
-{ lib, stdenv, fetchgit, curl }:
+{ lib, stdenv, fetchFromGitHub, curl }:
 
 stdenv.mkDerivation {
   pname = "metar";
-  version = "20161013.1";
+  version = "unstable-2017-02-17";
 
-  src = fetchgit {
-    url = "https://github.com/keesL/metar.git";
+  src = fetchFromGitHub {
+    owner = "keesL";
+    repo = "metar";
     rev = "20e9ca69faea330f6c2493b6829131c24cb55147";
     sha256 = "1fgrlnpasqf1ihh9y6zy6mzzybqx0lxvh7gmv03rjdb55dr42dxj";
   };
@@ -14,8 +15,6 @@ stdenv.mkDerivation {
 
   meta = with lib; {
     homepage = "https://github.com/keesL/metar";
-    license = licenses.gpl2;
-    maintainers = [ maintainers.zalakain ];
     description = "Downloads weather reports and optionally decodes them";
     longDescription = ''
       METAR reports are meteorogical weather reports for aviation. Metar is a small
@@ -27,5 +26,7 @@ stdenv.mkDerivation {
       more work in the area of clouds need to be done, as support for Cumulus or
       Cumulunimbus is not yet decoded.
     '';
+    license = licenses.gpl2Plus;
+    maintainers = with maintainers; [ zalakain ];
   };
 }