Add new workshop entry for Helmholtz Zentrum (#613)

* Add new workshop entry for Helmholtz Zentrum

Author: joshigunjan

workshops.md

@@ -15,3 +15,4 @@
 | 2025-01-28        | Netherlands eScience Center | Amsterdam, The Netherlands |          |
 | 2025-03-03        | CASTIEL2                    | Online                     | Part of a course `Multi-GPU AI Train-the-Trainer` |
 | 2025-05-06        | EuroCC National Competence Center Sweden | Online        |          |
+| 2025-10-27 to 29      | Helmholtz-Zentrum Dresden-Rossendorf, Germany | Online        |          |