Fix the Django Example (#1184)

## Summary

1. Updates python + pip package versions to align with stdenv (maybe?)
2. Install pip packages using
[pep517](https://peps.python.org/pep-0517/)

## How was it tested?

Tested in Devbox Cloud 

https://github.com/jetpack-io/devbox/?branch=jl/django-fix&folder=examples/stacks/django
(Wow what a handy feature)

Author: Lagoja

examples/stacks/django/devbox.json

@@ -1,8 +1,8 @@
 {
   "packages": [
-    "python310",
+    "python@latest",
+    "python311Packages.pip@latest",
     "openssl@latest",
-    "python310Packages.pip",
     "postgresql@latest"
   ],
   "env": {
@@ -11,7 +11,7 @@
   "shell": {
     "init_hook": [
       ". $VENV_DIR/bin/activate",
-      "pip install -r requirements.txt"
+      "pip install -r requirements.txt --use-pep517"
     ],
     "scripts": {
       "create_db": [

examples/stacks/django/devbox.lock

@@ -8,17 +8,21 @@
     },
     "postgresql@latest": {
       "last_modified": "2023-05-01T16:53:22Z",
-      "plugin_version": "0.0.1",
+      "plugin_version": "0.0.2",
       "resolved": "github:NixOS/nixpkgs/8670e496ffd093b60e74e7fa53526aa5920d09eb#postgresql",
       "version": "14.7"
     },
-    "python310": {
+    "python311Packages.pip@latest": {
+      "last_modified": "2023-05-01T16:53:22Z",
       "plugin_version": "0.0.1",
-      "resolved": "github:NixOS/nixpkgs/f80ac848e3d6f0c12c52758c0f25c10c97ca3b62#python310"
+      "resolved": "github:NixOS/nixpkgs/8670e496ffd093b60e74e7fa53526aa5920d09eb#python311Packages.pip",
+      "version": "23.0.1"
     },
-    "python310Packages.pip": {
+    "python@latest": {
+      "last_modified": "2023-05-01T16:53:22Z",
       "plugin_version": "0.0.1",
-      "resolved": "github:NixOS/nixpkgs/f80ac848e3d6f0c12c52758c0f25c10c97ca3b62#python310Packages.pip"
+      "resolved": "github:NixOS/nixpkgs/8670e496ffd093b60e74e7fa53526aa5920d09eb#python311",
+      "version": "3.11.3"
     }
   }
-}
+}