Fix download_url for windows agent installation
Fix download_url for windows agent installation

The download URL for the windows agent installer is using a different URL pattern than is currently
in use on the thoughtworks website. This change updates to use the current pattern. The URL for the
server install seems to be fine.

varshavaradarajan/go-cookbook,varshavaradarajan/go-cookbook,xmik/go-cookbook,varshavaradarajan/go-cookbook,xmik/go-cookbook,xmik/go-cookbook