fix to case

Author: barbarer

pretext/functions/func-group.ptx

@@ -1,5 +1,5 @@
 <?xml version="1.0"?>
-<Worksheet xml:id="func_basics_groupsub" groupwork="yes" groupsize="4" label="func-group">
+<worksheet xml:id="func_basics_groupsub" groupwork="yes" groupsize="4" label="func-group">
   <title>Group Work: Functions</title>
         <p>It is best to use a POGIL approach with the following. In POGIL students work
             in groups on activities and each member has an assigned role.  For more information see <url href="https://cspogil.org/Home" visual="https://cspogil.org/Home">https://cspogil.org/Home</url>.</p>