Merge pull request #616 from haylinmoore/nix-add-python3

default.nix: add python3 to the shell

default.nix

@@ -4,6 +4,7 @@ in
   pkgs.mkShell {
     buildInputs = [
       pkgs.platformio
+      pkgs.python3
       # optional: needed as a programmer i.e. for esp32
       pkgs.avrdude
     ];