frobnitzem: Update presentations by 2023-02-02

[bernhold]

• [x] "Update https://github.com/bssw-tutorial/presentations/blob/master/testing-a.pptx by 2023-02-02"
• [x] "Remember to update <https://github.com/bssw-tutorial/presentations/blob/master/presentations.yml if any titles change!"

[frobnitzem]

Instead of testing-a, I plan to use testing-advanced. I updated presentations.yml in the PR #149

[bernhold]

Merged