fio: 3.14 -> 3.15

Semi-automatic update generated by
https://github.com/ryantm/nixpkgs-update tools. This update was made
based on information from
https://repology.org/metapackage/fio/versions

pkgs/tools/system/fio/default.nix

@@ -4,13 +4,13 @@
 
 stdenv.mkDerivation rec {
   name = "fio-${version}";
-  version = "3.14";
+  version = "3.15";
 
   src = fetchFromGitHub {
     owner  = "axboe";
     repo   = "fio";
     rev    = "fio-${version}";
-    sha256 = "1qpv9saar0ik9mqpdyv93miyllfn7n7czcpffhk13lcrxasmjcp9";
+    sha256 = "0wzy5byc2qx5mbnwkcyjkrzc662n4wkrzpcg4h611q4ix494zka9";
   };
 
   buildInputs = [ python zlib ]