Enhancement request: Use deterministic UID/GID in Dockerfile

[ghsa-retrieval]

Is your enhancement request related to a problem? Please describe.
The UID and GID in the Dockerfile can change since the user and group are only created by name. This has implications for deployments that rely on identifying the user exactly. For example: Settings for the security context in Kubernetes/Helm charts, such as runAsUser and runAsGroup, cannot be applied, since the UID and GID are not known ahead of time and may change between versions.

What are the benefits of the requested enhancement?
The user and group are no longer assigned a non-deterministic ID. You can set up user namespaces in a predictable way.

Describe the solution you would like
Modify the adduser and addgroup commands in the Dockerfile to use a numerical UID and GID instead of a name. The UID and GID should be ones that are not already occupied by the Python base image.

Additional notes
Using a numerical UID and GID instead of name is also recommended according to Docker: https://docs.docker.com/build/building/best-practices/#user