Specify Python version in render config

.render.com/build.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 set -o errexit
 
-python3 -m pip install --upgrade pip
-pip3 install -r requirements.txt
+python -m pip install --upgrade pip
+pip install -r requirements.txt
 
-python3 manage.py migrate
+python manage.py migrate

render.yaml

@@ -10,12 +10,14 @@ services:
     buildCommand: "./.render.com/build.sh"
     startCommand: "gunicorn babybuddy.wsgi:application"
     envVars:
-      - key: DJANGO_SETTINGS_MODULE
-        value: babybuddy.settings.render
       - key: DATABASE_URL
         fromDatabase:
           name: babybuddy
           property: connectionString
+      - key: DJANGO_SETTINGS_MODULE
+        value: babybuddy.settings.render
+      - key: PYTHON_VERSION
+        value: 3.10.4
       - key: SECRET_KEY
         generateValue: true
       - key: WEB_CONCURRENCY