Update assets/javascripts/templates/pages/about_tmpl.coffee

Co-authored-by: Simon Legner <Simon.Legner@gmail.com>

assets/javascripts/templates/pages/about_tmpl.coffee

@@ -678,7 +678,7 @@ credits = [
     'https://doc.qt.io/qt-5/licensing.html'
   ], [
     'R',
-    '1999--2012 R Foundation for Statistical Computing',
+    '1999–2012 R Foundation for Statistical Computing',
     'GPL',
     'https://svn.r-project.org/R/trunk/COPYING'
   ], [