python3Packages.dask: disable network tests

There were hydra failures (https://hydra.nixos.org/build/141870744/nixlog/1) for some tests requiring data on github (failing on mac and linux), and tests requiring local network access on mac.
Disable the former and enable the latter.

pkgs/development/python-modules/dask/default.nix

@@ -72,7 +72,10 @@ buildPythonPackage rec {
       --replace "cmdclass=versioneer.get_cmdclass()," ""
   '';
 
-  pytestFlagsArray = [ "-n $NIX_BUILD_CORES" ];
+  pytestFlagsArray = [
+    "-n $NIX_BUILD_CORES"
+    "-m 'not network'"
+  ];
 
   disabledTests = [
     "test_annotation_pack_unpack"
@@ -82,6 +85,8 @@ buildPythonPackage rec {
     "test_auto_blocksize_csv"
   ];
 
+  __darwinAllowLocalNetworking = true;
+
   pythonImportsCheck = [ "dask.dataframe" "dask" "dask.array" ];
 
   meta = with lib; {