python3Packages.aplpy: fix with latest matplotlib

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

@@ -27,13 +27,26 @@ buildPythonPackage rec {
     sha256 = "239f3d83635ca4251536aeb577df7c60df77fc4d658097b92094719739aec3f3";
   };
 
-  patches = [ (fetchpatch {
-      # Can be removed in next release after 2.0.3
+  patches = [
+    # Fixes compatibility with astropy-helpers. This patch has been merged into
+    # the master branch as of May 2020, and should be part of the next
+    # upstream release (v2.0.3 was tagged in Feb. 2019).
+    (fetchpatch {
       url = "https://github.com/aplpy/aplpy/pull/448.patch";
       sha256 = "1pnzh7ykjc8hwahzbzyryrzv5a8fddgd1bmzbhagkrn6lmvhhpvq";
       excludes = [ "tox.ini" "azure-pipelines.yml" ".circleci/config.yml" "MANIFEST.in" ".gitignore"
        "setup.cfg" "appveyor.yml" "readthedocs.yml" "CHANGES.rst" ".gitmodules" ".travis.yml" "astropy_helpers" ];
     })
+    # Fix for matplotlib >= 3.4 (https://github.com/aplpy/aplpy/pull/466)
+    # Note: because of a security thing, github will refuse to serve this patch from the
+    # "normal" location
+    # (https://github.com/aplpy/aplpy/commit/56c1cc694fdea69e7da8506d3212c4495adb0ca5.patch)
+    # due to the fact that it contains the PDF magic bytes, but it will serve it from
+    # this githubusercontent domain.
+    (fetchpatch {
+      url = "https://patch-diff.githubusercontent.com/raw/aplpy/aplpy/pull/466/commit/56c1cc694fdea69e7da8506d3212c4495adb0ca5.patch";
+      sha256 = "0jna2n1cgfzr0a27m5z94wwph7qg25hs7lycrdb2dp3943rb35g4";
+    })
   ];
 
   propagatedBuildInputs = [