fix: Add dependencies of canvas NodeJS library

Add additional darwin dependencies to fix the node-canvas install script
failing with missing dependency errors.

Author: srounce

devenv.nix

@@ -23,7 +23,12 @@
       libgcc
     ] else [];
     darwin-only-pkgs = if pkgs.stdenv.isDarwin then with pkgs; [
-    ] else [];
+      pixman
+      cairo
+      pango
+    ] ++ (with pkgs.darwin.apple_sdk.frameworks; [
+      CoreText
+    ]) else [];
   in system-packages ++ python-packages ++ linux-only-pkgs ++ darwin-only-pkgs;
 
   enterShell = ''