[OpenSymPaper] Repair umlaut

opensym-paper/paper/sample-sigconf.tex

@@ -85,7 +85,7 @@
 %% used to denote shared contribution to the research.
 \author{LV}
 \affiliation{%
-  \institution{Freie Universität Berlin}
+    \institution{Freie Universit{\"a}t Berlin}
   \country{Germany}}
 \email{bla@blup.com}