docs(index): update current and previous roles

Move the item about serving on the SIGCSE TS 2024 program committee from 'Currently participating' to 'Previously played an active role in'. This reflects a change in the engagement status with SIGCSE TS 2024.

The removal of the SIGCSE TS 2024 item from the current participation section suggests the author's active involvement has ended, while the addition under the previous activities indicates recognition of past contributions. There are no other changes or significant implications mentioned in the diff provided.

index.md

@@ -34,7 +34,6 @@ I find it important to contribute to our academic society. I am also looking at
 
 Currently, I am participating in the following:
 
-- I am a member of the program committee of SIGCSE TS 2024
 - I am member of the student council of the [Institute for Programming research and Algorithmics](https://ipa.win.tue.nl/).
 - I am a member of the NHL Stenden knowledge group Design Based Education 
 - I am lecturing the LaTeX workshop at Open Universiteit
@@ -44,6 +43,7 @@ Currently, I am participating in the following:
 
 Previously I have played an active role in the following items:
 
+- I served as a member of the program committee of SIGCSE TS 2024
 - I was one of the organizers of the [evaLuation and assEssment on softwARe eNgineers' Education and tRaining](https://unibas3d.github.io/learner/) (LEARNER) 2023 workshop, which is part of the [International Conference on Evaluation and Assessment in Software Engineering](https://conf.researchr.org/home/ease-2023) (EASE-2023)
 - I was a member of the organizing committee of [NIOC 2023](http://nioc.nl).
 - I was one of the student competition chairs of [A-Test 2022](https://a-test.org/).