:wrench: Update node version in Dockerfile.

[JonasGilg]

Description

Update the version of the docker container to use node 20.

I, the reviewer checked the following things:

• [ ] I ran the software once and tried all new and related functionality to this PR
• [ ] I looked at all new and changed lines of code and commented on possible problems
• [ ] I read the added documentation and checked if it is understandable and clear
• [ ] I checked the added tests for completeness
• [ ] I checked the internationalized strings for spelling errors
• [ ] I checked the performance metrics for problems or unexplained degradation
• [ ] I checked that the changes are noted in the changelog

[github-actions[bot]]

Test Results

34 tests  ±0   34 :white_check_mark: ±0   10s :stopwatch: -1s 15 suites ±0    0 :zzz: ±0   1 files   ±0    0 :x: ±0 

Results for commit c6d981a3. ± Comparison against base commit 83c3ffa6.