fix(getgroupmembers): widen membername to $256 for long names

mv_getgroupmembers declared the member name at $43, and a longer name was
truncated - or, on Viya, stopped the step with "Multiple lengths were
specified".

membername is declared at $256 in the same shape the macro now returns it: one
width for every group, so the tables the caller combines are never of differing
lengths, and a long active directory name is kept whole.

sas/sasjs/targets/viya/macros_viya/dc_getgroupmembers.sas

@@ -7,7 +7,7 @@
   <h4> SAS Macros </h4>
   @li mv_getgroupmembers.sas
 
-  @version 3.4
+  @version 3.5
   @author 4GL Apps Ltd
   @copyright 4GL Apps Ltd.  This code may only be used within Data Controller
     and may not be re-distributed or re-sold without the express permission of
@@ -16,8 +16,11 @@
 
 %macro dc_getgroupmembers(group,outds=dc_getgroupmembers);
   %mv_getgroupmembers(%str(&group),outds=&outds)
+  /* membername is declared at the same $256 mv_getgroupmembers uses: the caller
+    combines the group tables, and a data step will not combine a variable of
+    differing lengths */
   data &outds ;
-    length membername $64;
+    length membername $256;
     set &outds(rename=(name=MemberName));
   run;
 %mend dc_getgroupmembers;