component/imagemagick: fix download URL for older versions
All of my Test Suites got Invalidated, saying:
Error: Error downloading https://www.imagemagick.org/download/releases/ImageMagick-7.1.2-16.tar.xz: HTTP Error 404: Not Found
Apparently, the link to get ImageMagick only has the latest version available. With this fix, we use archive link that has a lot more older versions.