Bump cryptography from 44.0.0 to 50.0.0 in /sample-apps/django-mysql - #679

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4, actions/setup-python@v5, grafana/setup-k6-action@ffe7d7290dfa715e48c2ccc924d068444c94bde2, nick-fields/retry@14672906e672a08bd6eeb15720e9ed3ce869cdd4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/