[Snyk] Security upgrade python from 3.13.0a5-alpine to 3.13.3-alpine

[jamesgeddes]

Snyk has created this PR to fix 5 vulnerabilities in the dockerfile dependencies of this project.

Keeping your Docker base image up-to-date means you’ll benefit from security fixes in the latest version of your chosen image.

Snyk changed the following file(s):

• docker/backend/Dockerfile

We recommend upgrading to python:3.13.3-alpine, as this image has only 0 known vulnerabilities. To do this, merge this pull request, then verify your application still works as expected.

Vulnerabilities that will be fixed with an upgrade:

	Issue	Score
	Integer Overflow or Wraparound SNYK-ALPINE319-EXPAT-7908400	714
	Integer Overflow or Wraparound SNYK-ALPINE319-EXPAT-7908409	714
	XML External Entity (XXE) Injection SNYK-ALPINE319-EXPAT-7908399	614
	Uncontrolled Recursion SNYK-ALPINE319-EXPAT-9459844	614
	Use After Free SNYK-ALPINE319-BUSYBOX-6928846	514

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Important

• Check the changes in this PR to ensure they won't cause issues with your project.
• Max score is 1000. Note that the real score may have changed since the PR was raised.
• This PR was automatically created by Snyk using the credentials of a real user.

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Learn how to fix vulnerabilities with free interactive lessons:

🦉 XML External Entity (XXE) Injection
🦉 Use After Free