Fix citation author in subset README

pointerbench-sheets/README.md

@@ -182,7 +182,7 @@ reused for training. The generator and the exact build command live in the
 ```bibtex
 @misc{pointerbench_sheets_2026,
   title  = {Pointerbench-Sheets: A GUI Grounding Benchmark for Spreadsheets},
-  author = {Pointerbench-Sheets contributors},
+  author = {Maximilian Schilling and Warmwind AG},
   year   = {2026},
   url    = {https://github.com/warmwindOS/pointerbench}
 }