For those who want to download the package file from within SAS can use the following code to do it:

filename pkg "c:\temp\polygon.zip";
proc http
url="https://communities.sas.com/kntur85557/attachments/kntur85557/sas_iml%40tkb/30/1/polygon.zip"
out=pkg
;
run;

proc iml;
package uninstall polygon;
package install pkg;
quit;