Attempting to fix SQLite errors in Squash deployments by updating Docker image (#8757)

.squash.yml

@@ -1,6 +1,6 @@
 deployments:
   default:
-    dockerimage: python:3.7.4-stretch
+    dockerimage: python:3.10.5-slim-buster
     build_steps:
       - apt-get update && apt-get install -y libssl-dev libpq-dev git build-essential libfontconfig1 libfontconfig1-dev curl
       - RUN bash -c "curl -sL https://deb.nodesource.com/setup_16.x | bash -"
@@ -8,7 +8,7 @@ deployments:
       - pip install setuptools pip --upgrade --force-reinstall
       - cd /code
     post_build_steps:
-      - npm install --no-save --no-audit --progress=false
+      - npm ci --audit=false --progress=false
       - npm run build
       - pip install /code
       - mkdir /myproject
@@ -18,6 +18,7 @@ deployments:
       - python manage.py migrate
       - echo "<br><h1>Wagtail test instance</h1><p>Log into <a href='/admin/'>/admin/</a> with 'admin' / 'changeme'.</p>" > home/templates/home/welcome_page.html
       - echo "from django.contrib.auth import get_user_model; User = get_user_model(); User.objects.create_superuser('admin', 'admin@example.com', 'changeme')" | python manage.py shell
+      - echo "CSRF_TRUSTED_ORIGINS = ['https://*.squash.io']" >> mysite/settings/dev.py
     launch_steps:
       - cd /myproject/mysite
       - python manage.py runserver 0.0.0.0:80